Chocolate Consumption and Purchasing Behaviour Review: Research Issues and Insights for Future Research

: Chocolate is consumed all over the world. Since its origin, it has undergone many transformations to meet changing market demand. A better understanding of consumer behaviour is a key objective of any business, and so it is for chocolate businesses. In order to fulfil this aim, the current study presents a systematic literature review of consumers’ consumption and purchasing behaviour towards cocoa and chocolate. Two databases have been used to collect the literature: Scopus and Web of Science. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram was used to identify the articles through the process of data screening and extractions. A total of sixty-four scientific articles have been selected. Research topics, methodological approach and data collection method were identified for each article selected. Then, the identified topics were grouped into four categories in order to obtain a model of major determinants in chocolate consumption: personal preferences, product attributes, socio-demographic factors and economic attributes. Results show that there is a strong focus on Fair Trade in chocolate. Moreover, the current literature review supports the fact that the price and promotion are under-investigated issues. This research represents a valuable tool, especially from a marketing point of view, by creating new channels and new sales opportunities for chocolate products.


Introduction
Chocolate is an accessible luxury [1] that we treat ourselves to for personal gratification [2][3][4][5][6].It has undergone a significant transformation since its origins, going from being a simple drink consumed by indigenous people [7] to a specialty product.
The main ingredient of chocolate is cocoa.Over the last 40 years, there has been a discontinuous but steady growth in cocoa production.Approximately 1.6 million tonnes of cocoa was produced worldwide during the crop year 1980/81.Almost 5 million tonnes of cocoa were produced in the last crop year 2018/19 [8] with 2.5 million tonnes produced on the Ivory Coast [9], which, together with Ghana, covers the demand of 60% of all cocoa used for chocolate production in the world [10].
Chocolate is consumed all over the world, and the largest chocolate manufacturers are based in North America and Europe [11].Top consumers are the Swiss (8.8 kg/year/per capita), and bottom level consumers are the Chinese (100 g per year/per capita) [12].
Chocolate formulation is in constant evolution.The changes aim to meet the evolving demands of food consumers.There is an increasing request for a low-calorie chocolate without sugar and a vegan product formulation without animal derivatives [13].However, there is no systematic review of the literature that reports the results of past studies on cocoa and chocolate consumer purchasing and consumption behaviour.
Thus, the purpose of the present literature review is to: This literature review provides an overview of the major determinants in chocolate consumption.Understanding consumers' preferences, perceptions and motivations in purchasing behaviours allows us to target a greater number of consumers and thus create new channels and new sales opportunities for chocolate products.
The structure of the paper is as follows.Section 2 provides a description of the search strategy and selection criteria that have been applied to identify the papers for the current literature review.Section 3 collects the results divided into the four categories identified.Further areas of research and conclusions are presented in Sections 4 and 5, respectively.

Methods
In order to identify, organize and analyse the literature on consumer purchasing and consumption behaviour towards chocolate and cocoa, a systematic review [14] of the studies conducted to date has been carried out.The study followed a structured protocol.Figure 1 outlines the research method and the criteria for selecting relevant articles in the literature.The results of study selection will be presented based on a PRISMA flow diagram [15].Articles excluded on the basis of title, abstract and journal because they did not focus on cocoa or chocolate (n = 214) Full-text articles excluded because they did not focus on consumer behaviour (n = 9)

Search Strategy
The research papers have been retrieved through a systematic search of peer-reviewed journals.Two databases have been used to collect the literature: Scopus and Web of Science.A combination of search terms was used to identify the studies that focused on consumer purchasing and consumption behaviour towards cocoa and chocolate.The authors identified a search string where four separate groups of words were combined and then applied to both databases (Table 1).The first group of words included "cocoa OR chocolate".The aim is to include at least one of the two words identified, including multi-product studies.To ease the reading, the current paper will exclusively refer to the term chocolate.In the second group of words, the terms "consumer OR purchasing OR purchase" were included in order to focus the research on those studies based on the analysis of consumer purchasing and consumption behaviour research.The third group of terms included the following sequence of words: "perception OR behaviour OR attitudes OR attributes" OR "willingness-to-pay" OR "willingness to pay".This combination of words aimed to retrieve the papers that focused on consumers' perception, attitudes, behaviour and willingness to pay for different attributes.The present review excludes articles on the sensory perception of consumers.Thus, the string includes "AND NOT sensory" in the last group.Finally, restrictions have been placed on the document type, limiting the search to articles and reviews published after the year 2000.In Scopus, the research has been conducted in the field abstract, title and keywords for the first three groups of words, and in the abstract for the last group.In Web of Science, the search field was Topic.Through the specific combination of words and the limitation of the search field, a first group of articles was identified for further screening.The research paper databases were consulted in January 2020.

Selection Criteria
The research conducted on Scopus and Web of Science identified 196 and 221 articles, respectively, for a total of 417 articles.After elimination of duplicates, the remaining 287 articles were first evaluated on the basis of a) abstract, b) title, and c) journal.Then, the original database was reduced to 73 articles, which were analysed in depth by assessing the full text.Studies not in English, not focused on cocoa or chocolate or not related to consumer behaviour were removed.Studies in which chocolate was analysed only as a food ingredient (e.g., chocolate biscuits, chocolate cake or pudding, chocolate milk) were also excluded.As a result, a final set of 64 articles have been identified for an in-depth analysis of the research.A database was then built to analyse key data for each study.The key information included are: (1) author, (2) year of publication, (3) objective, (4) measurement method, (5) sample size, (6) sample composition, (8) data elaboration, (8) main research topics, (9) secondary research topics and (10) country.The description of primary studies included in the review can be found in Supplementary Materials.Thematic groups have been created to categorize the factors of chocolate consumption and purchasing consumer behaviour.This has allowed a clear and detailed understanding of the drivers that influence the chocolate consumer.Future research could build on the gaps highlighted in the current literature review.

Methodological Approaches and Research Issues of Selected Papers
The revised studies addressed a number of research topics and adopted various methodological approaches.Table 2 shows the methodological approaches adopted in the research papers.Forty-two papers developed choice experiments, experiments in the field or laboratory, experimental auctions and eye-tracking.Nine papers conducted a survey, and seven conducted an exploratory study, including one with a qualitative approach through the use of a diary as a data collection method.Table 3 shows the different data collection methods used by various research studies.The most widely used data collection method was the close-ended questionnaire (forty-eight out of sixty-four studies).Nine of these also included open-ended questions.The other ten studies carried out interviews, diary reading and focus groups.No. Authors Questionnaire 48 [1-6,17,19,20-23,25,27,29-34,36-42,44,46,47,49- The analysis of the 64 papers collected led to the identification of various preferences, attributes and factors that drive chocolate consumption and purchasing behaviour.These were identified as the main research topics and grouped into four categories: (1) personal preferences, (2) product attributes, (3) socio-demographic factors, and (4) economic attributes.
Taste and health-related reasons have been included in the category "personal preferences", which influence chocolate consumer behaviour."Product attributes", which have been divided into Fair Trade, packaging, organic, brand, size, country of origin and genetic modification, affect the type of chocolate consumed.Furthermore, price and promotions, included in the "economic attributes" category, determine consumer purchasing behaviour.Finally, the influence of age, gender and income on consumers' preferences have been grouped in the "socio-demographic factors" category.
Figure 2 provides a comprehensive picture of the topics and groupings of topics by number of research studies.Research topics and frequencies-primary or secondary.Note: The number outside the parentheses is the topic frequency as the main topic.The number inside the parentheses is the topic frequency as the secondary topic.For example, nine papers address the health issue as the main topic, and five as a secondary one.
Past consumer research on chocolate consumption and purchasing behaviour has focused strongly on the issue of sustainability and ethical consumption (nineteen out of fifty-four papers).Most of the reviewed literature on sustainable consumption and purchasing behaviour used a willingness-to-pay approach [3,4,17,21,30,34,36,42,44,45,47,55], five of which through the auction system [21,34,44,45,47].The use of visual stimuli within the research studies that focused on sustainability issues has been applied in five studies [30,34,38,53,55].Among them, only one has projected a video [30], whereas the other research studies have employed images of existing products or images modified ad hoc for the experiment.The choice experiment methodological approach has been adopted in five studies [3,4,[16][17][18], using questionnaires and interviews as the data collection method.All papers dealing with sustainability issues have adopted questionnaires.One study created an online questionnaire, simulating a real shopping experience [40].Another study took place at a shopping stand where Fair Trade products were sold, in order to observe consumer behaviour [23].
The effects of packaging, including portion size, on the chocolate consumer has been the second most explored issue.Packaging is crucial when choosing a food product, and especially so for chocolate.The research studies address the packaging topic from different perspectives.Two articles analyse the impact of sustainable packaging on the consumer, respectively through a choice experiment [17], and through an eye-tracking experiment [38].Two articles analyse the effect that "deceptive" practices such as colour imitation [29] or deceptive air-filling of packaging can have [39].Both use an experimental approach with visual stimuli.One research study observes consumers' reactions to the exterior colour of chocolate [24].Two research studies explore the consumer interest in packaging appearance and attractiveness [57,66] using a questionnaire and semi-structured indepth interviews respectively.Finally, through an eye-tracking experiment on a computer screen and an experiment using a questionnaire, two studies analyse how consumers focus on different information elements of packaging [25,48].
The relevance of the chocolate portion size on consumers was addressed by six studies [2,22,33,43,57,63].They used different approaches and data collection methods.In particular, this topic was analysed through interviews, questionnaires (on-site and online), auction, games, and taste experiments.
Health is another key issue addressed.It was addressed in nine studies [25,26,31,32,35,49,50,58,66].The health topic has been analysed, mainly through an experimental approach with the support of a questionnaire, except for two studies that used the implicit association test (IAT) to collect the data [26,35].Of all sixty-four papers, the IAT was used only in this case.The use of visual stimuli is quite frequent.Among the studies that used pictures or real products, one used the eye-tracking method, analysing the time the consumer's gaze stays on information about health or taste claims [49].
Another key issue is the influence of economic attributes of chocolate on consumer choices.The product price limitedly impacts the chocolate consumer's purchasing behaviour.However, discounts and promotions contribute to drive consumers' chocolate purchasing habits.According to Davis, consumers tend to switch the brands to benefit from sales promotion [20].The second study that addressed the issue of promotion is from Thaichon et al. (2018) [57].Davis and Millner's (2005) [20] study uses a questionnaire, combined with open questions, while Thaichon et al. (2018) [57] adopt a more qualitative approach through the use of semi-structured in-depth interviews.
Furthermore, it is important to note the evolution in the issues addressed by research studies on chocolate purchasing and consumption over time.The interest in sustainability, in all its dimensions, economic, social and environmental, has begun to exercise greater curiosity since 2015.In the years from 2000 to 2015, six studies have addressed the issue of sustainability [17,21,23,30,44,45].Bernard, Zhang and Gifford (2006) [21] addressed the issue of environmental sustainability, focusing on the consumers' perception of organic versus genetically modified (GM) chocolate.Then, consumers' attitudes towards Fair Trade sustainability was explored in 2008 [23].From 2015 onwards, the number of studies analysing consumers' perceptions of chocolate sustainability attributes have strongly increased [3,18,34,36,38,40,42,47,53,55,69,70],.Chocolate packaging started to interest researchers in 2009 [24], and a focus on chocolate sustainable packaging followed in 2014 [17].Only four studies deal specifically with the effect of price on the consumer, respectively in 2001, 2006, 2014 and 2018 [57][58][59]66].Among the various attributes of sustainability, Fair Trade is certainly the one that consumers value the most.Price exerts a limited power on consumers who put taste before any other attribute.
The geographical distribution of the various topics (Table 4) provides interesting insights.Sustainability plays an important role in thirteen consumer studies in Europe [3,4,17,30,34,36,38,42,44,47,53,55,69] and four in North America [18,21,23,40].No sustainability studies have been conducted in Asia or Oceania.Studies in Asia have been conducted in India [5,46,54,60,61], and one in Lebanon [64].In Asia, the topics addressed were the influence of the country of origin, genetic modification, brand, demographic factors and product affection.Some of the studies carried out a cross-country analysis by comparing different European chocolate consumers' behaviours [58,67].The issue of health is addressed for the first time in 2010, and only in six European focused studies [25,32,35,49,50,58], where it does not appear as a particular cause for concern for consumers.Packaging has been analysed seven times in Europe [17,24,25,29,38,39,48] and once in Australia [57], where it plays a relatively important role, both in terms of sustainability and attractiveness.Topics such as genetic modification and the economic attributes of chocolate have been addressed in different years and at different locations.Interest in GM chocolate does not appear in European studies, and it has not been addressed in the last four years.The influence of economic attributes, such as price and promotion, has been of interest to researchers in the first five years of the new millennium, and from 2014 onwards.No studies on the effect of promotion on chocolate have been carried out in Europe.Note: n.a.denotes not available.These are studies that did not specify where the research was carried out.

Taste
Taste is the crucial factor when purchasing and consuming chocolate.Although perception of taste is extremely personal [16,57], it remains the key factor influencing chocolate consumer behaviour [3,4,51,62,64,57 ].Past literature is consistent in arguing that consumers prefer the taste of handmade chocolate over commercial chocolate [13].Taste is the dominant factor for loyal consumers of the Cadbury Dairy Milk brand [61].
Two interesting and intertwined concepts are developed in the studies of Enax et al. (2015) [34] and Didier and Lucie (2008) [44].The first study supports that Fair Trade labelling has a positive influence on the perception of chocolate taste.The second study argues that the perception of Fair Trade labelling improves if the taste is good.This last statement is in line with Didier and Lucie (2010) [45] study, according to which, taste positively influences the willingness to pay for organic or Fair Trade products.
In recent years, research has explored the relation between taste and health.Healthy products are often perceived as not very tasty.The study of De Pelsmaeker et.al. [67] confirms this consumer perception.Consumers prefer chocolate sweetened with sugar rather than with sweetener.Chocolate consumers want to have a good taste, even if it is a healthier chocolate formulation.These results are in line with the study of Steinhauser, Janssen, and Hamm (2019) [49].The authors reveal that consumers, despite observing health information for longer, will choose based on taste information.

Health
Although chocolate is seen as an "unhealthy" product [26] because of high-calories, the health factor has not been widely studied in chocolate consumption research.Studies support the idea that the health attribute has limited impact on chocolate consumer behaviour [32,50,66].Advertisement focused on the health aspects of chocolate does not lead to particularly relevant results [25,49].On the contrary, focusing on nutritional aspects, highlighting the benefits of this product, could lead to a great impact on sales [49].The study by Visschers and Siegrist (2009) [25] analyses the consumer impact of nutritional labels with different formats.The chocolate products' labels with reference or summary information on chocolate healthier nutritional values (e.g., average fat content) have a negative impact on consumer inclination towards chocolate, compared to labels with standard nutrition information.Detailed nutritional information on calories and fat content contrast with consumer chocolate primary association that it is a hedonic product [25].One exception applies to Belgian consumers, who are more impulse-controlled [58].De Pelsmaeker et al. (2017) [67] show that, when Belgians consume filled chocolate, they are governed by health concerns rather than the pleasure of the moment.Moreover, consumers are more likely to make healthier choices when exposed to information about costs.This stimulates the consumer's sense of self-regulation.Consumers are better inclined towards healthy food choices when the price is taken into account [31].
Consumers consider organic chocolate [53] and handmade chocolate [13] as healthier than conventional and commercial chocolate, respectively.The healthiness of the product positively influences the perception of product quality.Lembregts and van Den Berg's (2019) [43] study supports the idea that the consumer is more sensitive to more "discretizing" information (such as the number of chocolates contained) than to less discretizing information (such as grams), even if they express the same quantity at weight level.This shows that representing information in a more 'discretized' way would lead consumers to assess the information more carefully and thus make healthier choices.
The act of buying chocolate often occurs on impulse, according to an implicit mechanism without conscious awareness.Adding logos on the packaging, especially concerning wellness attributes, prolongs the time needed by the consumer to process the information received.Adding this information has a positive impact on behaviours mediated by explicit intentions, which is driven by rational reasoning [35].
Finally, the relation between consumers' demographic characteristics and chocolate health claims was limitedly analysed.Only one study deals with this topic [50], and supported the idea that the consumers' age does not influence choice when it comes to health, and that women take health information into account more than men.

Country of Origin
Research on the impact of country of origin (COO) attribute on chocolate consumption is limited.Overall, the presence of COO has a positive influence on the consumer.However, more attention should be paid to the effect of "made in".It has been observed that the country of production has much more influence than the country of origin.This creates a close correlation between the brand and the country with which consumers associate it [62,64].A 2007 study supports the idea that the COO has a strong influence in the decision-making process of chocolate consumers [62], especially for Germans, whose perception of chocolate quality increases if the country of origin is indicated [68].The COO influences consumers more than ethical attributes [4].However, results show that in the case of such a low-involvement product, the consumer attaches more importance to factors that can be assessed more easily, such as brand and price [62].These conclusions are consistent with what was developed by Amhed et al. [64].They support the idea that the effect of the chocolate COO attribute on the decision-making process is less relevant than taste and price when it comes to lowinvolvement products such as chocolate.Similar insights can be gained from a study by Lybeck, Holmlund-Rytkönen and Sääksjärvi (2006) [51] in which "price was considered less so, as was country of origin".The authors also note that older people and women give more importance to the chocolate COO attribute compared to young people and men, respectively.In the study by Kozelová et al. (2014) [66], only 2% of respondents state that chocolate COO is important.However, these controversial stances may be due to the lack of information on the origin of ingredients [69], as a limited number of the studies explored the impact of COO on chocolate consumption.

Organic Labelled Chocolate and GM Product
Consumers mostly rely on organic labelling as a guarantee of human health and protection for the environment [3,17].A study by Bullock, Johnson and Southwell (2017) [40] shows that the health attribute has a crucial effect on consumer choices.They argues that advertising has an effect only if it is "related to protecting one's own and family health", rather than "activating ethical values".Banjarnahor, Napitupulu and Situmeang (2017) [70] stressed that chocolate advertised with selfbenefit information, rather than green-benefit, is considered less expensive and of higher quality.Furthermore, an interesting observation about chocolate emerges from the Didier and Lucie (2010) [45] study.It states that organic labelling is an added value for the consumer, who will perceive the product as being of better quality.This means that the awareness of buying a certified sustainable product improves the qualitative perception that the consumer has of the product.Hidalgo-Baz, Martoz-Partal and Gonzalez_Benito (2017) [53] also state that this is less accentuated in vice products, such as chocolate, rather than virtue products.
Consumers often have difficulties in understanding the meaning of labels.Consumers tend not to understand the difference between organic and Fair Trade [40], and to believe that organic chocolate uses Fair Trade cocoa [3].Rousseau (2015) [3] adds that a large number of consumers do not believe that the information on organic labels is reliable.Moreover, Young and McCoy (2016) [18] discover an interesting connection between choosing a sustainable label and the need to "reduce one's guilt".The consumers' approach towards buying organic goods or goods with another sustainability certification is similar, as they both satisfy a sense of responsibility.
Consumers who buy organic are also interested in the fact that the product is not genetically modified.Moreover, consumers who avoid genetically modified chocolate are those who buy the organic option.The fact that the product is not GM becomes more important than it being organic, and more important for organic consumers than for consumers of other types of chocolate [21].In general, millennials are limitedly concerned about GM attributes [18].Consumers' perceptions of GM products tends to depend on the level of knowledge and information consumers have on the topic.This is generally low [46].In general, the willingness to pay for GM chocolate increases when both positive and negative information is provided on the packaging rather than just positive information [46].
Sustainability attributes have more effect on consumers when combined among themselves.The organic label is more attractive when presented in combination with other sustainable certifications, rather than presented individually [17].These arguments stand in contrast with Didier and Lucie (2008) [44], who found that "the joint application of environmental and social labels on the same product induces a sub-additivity to the willingness to pay (WTP) compared with the WTP for the two dimensions considered separately".In addition, the willingness to pay for the organic attribute is higher for branded products [44].With regard to GMO products, it was noted that consumers are willing to pay more when both positive (e.g., minimum use of pesticides required) and negative (e.g., unknown effect on flora, fauna and soil) information is present rather than only positive information or lack of information [46].

Fair Trade Labelled Chocolate
Chocolate Fair Trade has been widely studied.Past studies approached it from different perspectives, such as the willingness to pay, the preference of Fair Trade certification over other sustainability attributes or conventional products, and the different purchase intention based on socio-demographic factors.Past research supports the idea that consumers prefer the Fair Trade label compared to other sustainability labels [3,17].Most consumers are willing to pay more for certified products than for those without certification [17], and among certifications, they are willing to pay more for "Fair Trade" than for other certifications (Rain Forrest Alliance or Carbon Footprint) [47].However, consumer awareness of ethical issues is limited.A study by Aktar (2013) [30] shows that consumers' perceptions of a chocolate company does not change, even when they are exposed to information about the use of unethical practices by that company.Even the WTP for that chocolate is not affected.
An interesting finding emerges from the Teyssier, Elité and Combris (2015) [36] study, which states that the willingness to pay a premium price for Fair Trade chocolate is closely linked to consumer self-image and the need to diminish a personal sense of guilt [18].The research conclusions support the fact that food choices are motivated by both the consumers perceived self-image and how they want to present themselves to others.This study notes how many consumers are influenced by the presence of an audience when choosing chocolate.The fact that their choice can be seen and observed by someone increases the premium price they are willing to pay for certified sustainable chocolate.This is motivated by the consumer's need to obtain social approval by buying ethically [42].Furthermore, past research support the idea that "pro-ethical" advertising campaigns have a positive impact on the consumers' willingness to pay and purchase intention toward Fair Trade chocolate [55].However, taste and price, followed by the origin of the ingredients, remain the main drivers for consumers of chocolate [3,4,44].The evaluation of the Fair Trade label also depends on the consumer's appreciation of taste [44,45], and vice versa [34].The more consumers appreciate the taste of Fair Trade chocolate, the more positively they will value this certification.The study by D'Astous and Mathieu (2008) [23] comes to interesting conclusions.On one hand, if the consumer's attention is not particularly high, the communication of information on Fair Trade in a "pallid" way appears to have a greater effect than information transmitted in a clear and "vivid" way.On the other hand, the immediacy and clarity with which information is communicated to the consumer does not have a particular effect if his attention on information is high.
Socio-demographics factors influence Fair Trade chocolate consumption.According to Mai (2014) [17], there are limited differences between men and women, and between different age groups, with respect to their willingness to pay for Fair Trade chocolate.Some studies show that women consider Fair Trade certification more important than men.Vecchio and Annunziata (2015) [47] claim that seniors, women and consumers with high incomes are willing to pay a higher price for Fair Trade chocolate.According to Poelmans and Rousseau (2016) [4], young women preferring white chocolate do not value the Fair Trade label.Consumers positively inclined towards the Fair Trade label tend to prefer chocolate bars and milk chocolate [4].
Brand has a positive impact on consumers and their intention to buy a certified Fair Trade product.Comparing market prices with consumers' willingness to pay for this attribute, Didier and Lucie's (2008) [44] study claims that, without the brand, consumers are willing to pay less than the actual price for Fair Trade chocolate.

Brand
Many studies have investigated the effects of various extrinsic attributes of chocolate on consumer choice, including the role of the brand.According to many authors, brand affects consumer's choice of chocolate [54,62,64,66] .Consumers are loyal to the brand as they associate it with particular parameters of quality and taste, which they are unlikely to abandon for other brands [62].For this reason, the effect of advertising certainly has a positive impact on the consumer, but not a decisive one [54].Affection towards a specific image presented on the product and the buying habit of a specific product can lead consumers to not change brands.If the consumer is not familiar with the product, even in the case of chocolate, it is difficult for it to be incorporated into the consumer's eating habits [37].Ahmed et al. (2012) [64] argue that chocolate is a low-involvement product.Thus, brand has a greater impact than price and country of origin (COO).The store-brand is preferred by middle-aged consumers [51].Previous chocolate consumption experiences lead consumers to become loyal to a particular brand, thus excluding others.An interesting study conducted by Bogomolova and Millburn (2012) [65] showed that brand, competition and consumers-related-motives are the main factors that influence chocolate consumers.In particular, unavailability or unawareness of a brand, preference for another brand or another taste, and health concerns are some of the reasons why consumers may not consider another brand.According to Bogomolova and Millburn (2012) [65], those who have never experienced a brand are more likely to exclude it a priori than those who have experienced it before.The non-exception of a brand can be determined by a lack of interest or by force of habit, which can lead the consumer to not change the familiar choice.Without familiarity with a brand, there would be no repurchase of that specific brand by the consumer [57].Only one study analyses the consumer response to chocolate commercialised with private labels versus corporate brands [52].

Packaging
Shekhar and Raveendran (2017) [71] and Thaichon et al. (2018) [57] argue that packaging plays a key role in chocolate purchasing behaviour.The packaging is particularly relevant as chocolate is often purchased as a gift for someone else.Thus, they argue that the quality of the chocolate is as important as the packaging that wraps it.If the consumer is not familiar with the product, he/she will choose the one with the most pleasant packaging.A study by Rebollar et al. (2015) [48] observed that the consumer's eye is primarily drawn to the size of the information on the packaging, and will tend to focus on the elements from left to right, and from top to bottom.The packaging message that combines these two patterns will be perceived by the consumer with a greater impact.Sustainable packaging positively influences the consumer's perception of the product quality.This becomes particularly effective when the chocolate product itself is not certified as sustainable [38].According to Mai (2014) [17], sustainable packaging is not particularly valued by consumers when it comes to high quality chocolate.However, it has more influence than sustainable certifications themselves, especially among the elderly.
Wilkins, Beckenuyte and Butt (2016) [39] focus on consumer reactions regarding a "deceptive filling" of packages caused by a high volume of air filling rather than chocolate.The study shows that consumers may initially be deceived by "misleading packaging and slack filling".Through these strategies, consumers may initially be enticed to buy that package.However, this mechanism is not likely to last, having negative long-term repercussions [39].Only one study claims that chocolate packaging is the attribute least taken into account by consumers [66].
The colour of chocolate also influences the consumer's appreciation of a specific chocolate.A study by Shankar et al. (2009) [24] on M&Ms showed that consumers find brown M&Ms more "chocolatey" than coloured M&Ms, at least the green ones.Imitation of the brand's package design is more frequent than expected, especially in the case of chocolate.What emerges from van Horen and Pieters (2012) [29] is that consumers are quite aware of the possibility that some brands may resort to such "deception" by imitating certain features such as logo, colour or theme.Among them, the most accepted imitation by consumers is that of the theme, which they find more acceptable and less unfair.

Portion Size
Chocolate is a product of indulgence that consumers see as a gratification for themselves or as a gift for others [2][3][4][5]56,60,61].Chocolate is also seen as a comfort food.Consumption increases when we are sad and the reason is not dependent on us [6].For those who buy chocolate for their own consumption, consuming small units rather than one large unit gives the idea of acting more impulsively and therefore eating more.Thus, if consumers are given the same amount of chocolate as one single large portion, in separate units, they will tend to eat less [2].Eating smaller quantities of chocolate rather than the same quantity in one piece convinces the consumer that they have less product available [22].This forces them to eat it, taking more time to extend the tasting experience.Consumers will enjoy the tasting experience more, improving the perception of taste and satiety [33].
Small portions, in addition to being tasted more carefully, are also associated with a more "premium image and higher quality" chocolate [57].The size of the pack also influences the occasion of consumption.Larger packs are purchased to be consumed with other people, at work or at a party, smaller ones during sport as snacks.Finally, a further consideration emerges from the Vermeer, Bruins and Steenhuis (2010) [63] study, where it is observed that consumers are more inclined to consider the whole chocolate package as a portion and do not consider the units contained to be single portions.In addition, the perception of the portion size changes according to how "discretized" the information about that portion is given.Indicating the number of product units rather than the weight has a greater effect on consumers [43].
Finally, studies support the idea that the limited choice you have, the more satisfied the consumer will be with the choice they make, even in the case of chocolate [19].

Socio-Demographics Factors
A limited number of studies focused on the effect of socio-demographic factors on chocolate consumers' purchasing and consumption behaviour.This section presents past literature's findings focusing on gender, age and income.

Gender and Age
Age and gender impact on consumers' intentions to purchase certified chocolate.In general, the willingness to pay for chocolate is higher for women and the elderly [47].Women are sensitive to sustainable certifications, with particular attention to the organic label [17,47].However, Mai (2014) [17] supports the idea that women may not have a higher willingness to pay for chocolate sustainability labels.Men and women have a similar willingness-to-pay towards organic chocolate and Fair Trade.
Age may influence consumers' attitudes towards sustainability labels [17].Bullock, Johnson and Southwell (2017) [40] show that sustainability advertising has the biggest impact on consumers under 40 years of age.This is in contrast to the Chawla and Sondhi (2016) [60] study, which supports the idea that the search for sustainable values is effective when describing especially young consumers' behaviour.Older people prefer foreign brands, young people prefer national brands [5].Women, especially normal-weight women, are more sensitive to images of models placed on the chocolate packaging compared to overweight women.It has been shown by Durkin, Rae and Stritzke (2012) [27] that overweight women, when exposed to images of overweight models on the packaging, reduce their guilt in purchasing the product, but do not limit chocolate purchasing.

Income
Results on how consumers' income impacts chocolate consumers' behaviour are contradictory.The income factor seems to have no impact on the perception of chocolate [66] but has a positive influence on the consumer's willingness to pay [47].Few studies have investigated this aspect.In particular, one study focused primarily on this socio-economic trait, exploring the purchasing behaviour of consumers with high average income [3].
According to a study by Kozelová (2017) et al. [66], income has no particular influence on the consumer's purchase of chocolate.Income plays a key role in sustainability-certified chocolate.High income has a "positive and statistically significant effect" on consumers' willingness to pay for sustainable labels [47].Rousseau's (2015) [3] study investigated the effect of income on consumer choice.This research study finding confirms the positive effect of consumers' high income on the intentions to buy certified chocolate.

Economic Attributes
The impact of price on chocolate consumers' purchasing and consumption varies [57][58][59].The literature shows that different categories of consumers by age, gender, income and education are influenced differently by the price of chocolate [57][58][59].Chocolate is not identified univocally as an affordable luxury good or a necessity by consumers [1].A study by Stamer and Diller (2006) [59] identified five different categories of chocolate consumers, ranging from those who only consider price and those who only consider quality and brand.These categories differ in income, work career, family size and brand or quality consciousness.The other three groups include more conscious buyers, with higher career expectations, and who value quality and brand more.Lower-medium social classes, with no career orientation and large and uninformed families, give more importance to the price compared to other categories.
In a study by Kozelová (2017) et al. [66], the price is one of the attributes most taken into account among chocolate consumers.The price may be an incentive to consume less chocolate, especially for people on a diet [31].Consumers do not consider the price particularly relevant if the chocolate tastes good.However, it is more important than the country of origin [64].In a study by Thaichon et al. (2018) [57] on consumers of Cadbury Dairy Milk, price is not as important as taste.However, a promotional sale on other brands could lead consumers to change their purchase [57].The effect of the promotion on the consumer has not been particularly deepened so far.One study focuses on the analysis of which discount format has the greatest influence on chocolate consumers.This study shows that consumers are mainly attracted by the "buy one-get two" formula compared to " rebates" from the list price or simple price reductions [20].

Limitations
The present review has some limitations.All the analysed articles are written in English, thus excluding the results of studies in other languages.Moreover, only two databases were used for the selection of the papers.It would be convenient to consider using multiple sources.Only articles and reviews were considered from 2000 onwards.Finally, the search does not include articles published after January 2020, and these may have implications for future research.

Further Areas of Research
Over the years, how chocolate was consumed has changed from its origins to the present day.Initially, chocolate was a raw energy drink consumed at the time of the discovery of cocoa.Today, chocolate is a food product easily accessible, purchased for personal pleasure, which provides a sense of indulgent luxury.
Undoubtedly, taste plays a significant role for chocolate consumers, and the literature has extensively explored its importance.The literature review carried out supports the idea that chocolate is consumed to obtain a small temporary gratification.It is not a product in which health consideration is a major concern.The health aspect is hardly taken into account by the consumer, especially if it is at the expense of taste.
A beneficial area for further research could be to investigate which health and nutritional aspects consumers are most concerned about when they buy chocolate.This may provide insights into the development of new products that satisfy the consumers' increasing health-orientation.Future research may explore healthier chocolate reformulation and new product concepts, and innovative chocolate ingredients might be of interest to the consumer.Indeed, the single research study addressing the consumer's interest in chocolate with a sugar substitute supports the idea that consumers are limitedly interested in such a feature.
It is important that consumers perceive chocolate as a product that can be both healthy and tasty.Hence, it is useful to investigate how consumers taste healthier chocolate recipes in order to improve their perception.Such innovative chocolate formulations would lead to a wholesome and equally satisfying choice.
Moreover, the current literature review supports the idea that price and promotion are underinvestigated issues in relation to chocolate purchasing and consumer consumption behaviour.The buy-one-get-two formula is the promotion strategy most appreciated by chocolate consumers.This promotion may lead consumers to change their familiar chocolate brand.Further research could explore how consumers' consumption and purchasing behaviour change according to their perception of the price.It is relevant to understand consumers' knowledge and perception of the price partition between the various actors in the chocolate agro-chain.In particular, future research may investigate consumers' perceptions of the price distribution between chocolate producers, processors and retailers.Ensuring a perceived fairer remuneration may lead consumers to make more economically sustainable choices.
Due to the lack of studies correlating the emotional status of the consumer and his or her chocolate purchasing choices, it would be worthwhile to explore how purchasing behaviour changes according to the consumer's attitude.The research would complement recent results which state that chocolate purchasing is deeply affected by the mood of the consumer [6,72].
Future research may explore how consumers' behaviour changes in consideration of the context of chocolate use.There is a need to better understand how chocolate purchasing and consumption behaviour is influenced by the different occasions of use (e.g., chocolate used for cooking rather than a product to be eaten directly), and by the different occasions of consumption (e.g., for festivities or special occasions rather than for daily consumption).Such studies would allow us to obtain a more comprehensive understanding of chocolate consumer behaviour.This would allow us to better target a greater number of consumers, and to create new channels and new sales possibilities for chocolate products.

Conclusions
The present systematic analysis of the literature aimed to understand consumers' consumption and purchasing behaviour towards chocolate.The review allowed the categorisation of the factors influencing chocolate consumers in four groups: personal preferences, chocolate product attributes, socio-demographics factors, and economic attributes.This categorisation provides a comprehensive overview of the research themes, and of the methodological approaches adopted by past research.According to the reviewed literature, the methodological approach mostly adopted has been the experimental approach, both in the field and in the laboratory.The most widely used data collection tool was the questionnaire.
The consumer behaviour towards chocolate sustainability attribute is a key topic among researchers.The first study on sustainability was carried out in 2006, and it has significantly expanded since 2015, with specific interest in European studies.While it has been confirmed that chocolate is seen by consumers as a product of indulgence, and its purchasing and consumption is mostly driven by taste, it can also be stated that the Fair Trade sustainability attribute of chocolate is the sustainability product attribute that most attracts the consumer.Nevertheless, consumers are mainly motivated by their self-image, and the way they want to present themselves to others, rather than by a real interest in sustainability issues.
A chocolate attribute with a great impact on the consumer is the brand, which is rarely abandoned, representing for consumers particular parameters of quality and taste.Among other chocolate attributes, packaging and portion size play a fundamental role in the choice of chocolate.As chocolate is often purchased as a gift, it is important that it is not only good, but also that the packaging is attractive.Moreover, analysed studies concluded that small portions improve taste perception.The portion is smaller, the tasting time is longer and the perception of taste improves.
The health topic is mainly related the development of healthier alternative chocolate.However, it is not a major concern for consumers.
The chocolate consumers' socio-demographic factors and the chocolate product economic attributes have been limitedly explored in the literature.The analysis of the socio-demographic factors supports the idea that women and young people consider sustainability attributes as being more important compared to men and old people, respectively.However, men and women are equally willing to pay for these attributes.
The results on the influence of income on chocolate purchasing behaviour are contradictory.Income may make a difference when it comes to certified sustainable chocolate.This finding confirms the limited role of the price attribute on chocolate.As mentioned earlier, chocolate is a product mainly consumed for gratification or purchased as a gift.In both contexts, the economic attribute is not the first selection criteria driving chocolate consumer purchasing behaviour.Interesting, but limitedly explored, is the influence of promotion on chocolate consumers' purchasing and consumption behaviour.If taste is the factor that most increases loyalty to a specific product, promotion is the driving factor that could lead the consumer to betray the familiar brand for another.

Figure 1 .
Figure 1.Steps and criteria of literature search and screening process using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram.Note: Wos stands for Web of Science.
TITLE-ABS-KEY (cocoa OR chocolate) AND TITLE-ABS-KEY (consumer OR purchasing OR purchase) AND ABS (perception OR behaviour OR behaviour OR attitudes OR attributes OR "willingness-to-pay" OR "willingness to pay") AND NOT AND TITLE-ABS-KEY (sensory) AND DOCTYPE (ar OR re) AND PUBYEAR > 1999 196 Web of Science TOPIC: (cocoa OR chocolate) AND TOPIC: (consumer OR purchasing OR purchase) AND TOPIC: (perception OR behaviour OR behaviour OR attitudes OR attributes OR "willingness-to-pay" OR "willingness to pay") NOT TOPIC: (sensory) Refined by: DOCUMENT TYPES: (ARTICLE OR REVIEW) Timespan: 2000-2020 221

Figure 2 .
Figure 2.Research topics and frequencies-primary or secondary.Note: The number outside the parentheses is the topic frequency as the main topic.The number inside the parentheses is the topic frequency as the secondary topic.For example, nine papers address the health issue as the main topic, and five as a secondary one.
1. Investigate consumer behaviour towards chocolate purchasing and consumption; 2. Identify what factors influence chocolate purchasing and consumption behaviour; 3. Identify the most widely used methods for studying chocolate consumer behaviour; 4. Suggest possible gaps in the literature and thus provide insights for future research on chocolate consumption behaviour.

Table 1 .
Databases and terms used in this study and number of results obtained.

Table 2 .
Methodological approaches used in the selected studies.

Table 3 .
Data collection methods used in the selected studies.

Table 4 .
Location and year of publications of main research topics.