A Preliminary Lexicon for Juçara (Euterpe edulis Martius) Pulp: Possible Applications for Industry and Clinical Practice

Abstract

Juçara is an important element for biodiversity in the Atlantic Forest, not only providing a rich source of nutritional and bioactive compounds, but also holding promising potential for sustainability. However, despite its virtues, there remains a dearth of studies fully exploring its potential. In our pioneering study, conducted using a panel of eight trained specialists, we delved into a sensory analysis of dehydrated juçara pulp, employing both descriptive analysis and the temporal dominance of sensations (TDS) technique. The findings revealed striking differences between juçara and açaí, not only in terms of flavor and aroma, but also in their potential to drive more mindful eating habits. By promoting the consumption of juçara, we are supporting the sustainability of the Atlantic Forest, where it is cultivated in an environmentally responsible manner. Thus, we are contributing to the preservation of this unique ecosystem and the well-being of local communities.

1. Introduction

The juçara palm (Euterpe edulis Mart.), a native species of the Brazilian Atlantic Forest, holds significant ecological importance to the country such as for animal food, improving degraded areas, and as a source of income for the local population [1]. Despite this, the juçara palm is at risk of extinction. However, in recent decades, efforts have been made to promote the utilization of its fruit, a more sustainable alternative for plant use [2,3,4].

Juçara fruits weigh about 1 g, with a diameter of 1 to 1.5 cm [5]. The pulp, the main edible derivative of the fruit, is utilized in culinary applications, similar to açai, especially in sweet and cold food preparations [3,6]. In fact, in some markets in Brazil, açai and juçara are incorrectly sold as the same fruit.

Juçara pulp has exhibited potential bioactivity, which has been associated with a richness in macronutrients such as dietary fiber (4–5%), lipids (3–23%), protein (2–3%), and specific bioactive compounds such as anthocyanins (660–1609 mg.100⁻¹ g) [3]. In this context, our research group reviewed the recent literature on the potential uses of juçara for health benefits; we identified nine clinical trials where juçara was being studied for its modulation of the inflammatory response, antioxidant defense, prebiotic potential, genotoxicity, and epigenetic regulation, as well as the post-consumption metabolic effects of juçara [7]. That said, juçara presents an interesting opportunity for the food industry, grounded in problematic health indicators and environmental care [8].

On the other hand, the technological characteristics and sensorial profile of juçara pulp are not well elaborated in the scientific literature. So far, no studies have developed a lexicon or a sensory description of juçara pulp. In addition, to the best of our knowledge, only a single study has evaluated the sensory profile of juçara pulp, and this study focuses on the impact of thermal processing on the sensory quality of the pulp [9].

The construction of a descriptive sensory profile can play a vital role in various aspects of the food production chain, including product innovation, quality control, formulation refinement, and assessing the shelf life of food during storage [10], knowledge of which is required for the juçara pulp production chain. A descriptive sensory profile can capture a product’s characteristics (i.e., aroma, appearance, flavor, texture, aftertaste, and sound) using sensory panels to evaluate perceived sensory attributes [11].

Descriptive sensory models are the most sophisticated tools in the arsenal of the sensory scientist and comprise three distinct parts: the selection of a descriptive analysis panel, panelist training, and the selection of the evaluation method [12]. A crucial step in the process of descriptively analyzing a product is lexicon development, which can provide accurate and reproducible results for descriptive sensory analysis [13]. Lexicon development provides the opportunity to identify more relevant terms for intended product consumption scenarios [14].

Another descriptive methodology with the potential to characterize the sensory profile of foods is the temporal dominance of sensations (TDS), in which the perception of a food product as a temporal experience is studied in the sense that different sensory attributes are perceived at different times and with different intensities [15]. TDS is based on the concept of dominance. Nowadays, TDS is by far one of the most popular techniques used for multivariate temporal sensory analysis [16].

Thus, the purpose of this study was (1) to provide a preliminary sensory description of juçara pulp using a sample of dehydrated juçara pulp and (2) to evaluate the dominant sensation on the timely perception via TDS testing of this sample.

2. Material and Methods

2.1. Panelists

A total of 8 trained panelists able to communicate effectively in Portuguese, all women between 19 and 29 years old, participated in this study. All of them were students or worked as dietitians with prior experience of sensory analysis techniques. The panel underwent approximately 80 h of training in descriptive analysis that emphasized lexicon development. The group had no experience in evaluating juçara fruit or similar products, but all of them were willing to try juçara pulp as part of the study. All participants took part in the same group discussion.

2.2. Sample

Juçara pulp from the 2022 harvest (March to August) was used, originating from the Vale do Ribeira Paulista region, São Paulo, Brazil. The unpasteurized pulp underwent a dehydration process via spray drying with an 18.9 carrier (organic cassava maltodextrin). The process time and temperature were 5 s and 180 °C, respectively. The pulp used in this study had an average moisture and volatile content of 1% and a macronutrient composition of approximately 10% fat, 3% protein, and 86% carbohydrates. Its pH was 4.60. The physicochemical analysis for pulp characterization was performed at the Center of Science and Food Quality, Food Technology Institute, Brazil, following the NBR ISO 9001:2000 and NBR ISO/IEC 17025:2017 [17,18].

A sample drink was prepared with 35 g of dehydrated juçara pulp diluted in 150 mL of potable water with 8 g of sugar (4% of the total volume, 200 mL). The samples were served in plastic cups, with a capacity of 240 mL, coded by three digits chosen randomly. All samples were stored in a refrigerator at 5–7 °C before the test. The panelists cleaned their palates with water during the test.

2.3. Sensory Description

The panel evaluated the characteristics of the juçara pulp samples and developed terminology to describe them. Each evaluation session lasted approximately 1–2 h over 3 non-consecutive days. The panelists individually evaluated each sample and made notes on the descriptors presented. After all panelists finished their evaluations, the panel leader led a discussion to reach an agreement on the identified descriptors. Once the panel agreed on the descriptors, they suggested definitions and references, which could represent juçara pulp characteristics.

Complete lexicons have been reported in recent research on other products such as soy sauce, ham, and plant-based burgers [14,19,20]. In these studies, during lexicon selection, researchers provided additional samples and references to panelists upon request.

2.4. Analysis of the Temporal Dominance of Sensations

The same tasters in the trained panel participated in the temporal dominance of sensations analysis, and the same sample was offered. Panelists were asked to determine the dominant sensation over the analysis time (90 s, with a delay of 3 s). The test was performed using Sensomaker v.1.92 software and the order of descriptors was alternated for each participant.

At the beginning of the test, it was explained to the tasters that the dominant sensation is the one that stands out and is perceived with greater clarity than the others. The list of attributes used in the system was created during panelist training. We selected the most frequent terms in the first descriptive test: purple (color), fluid (texture), velvety (texture), greasy (flavor), earthy (flavor), sweet (taste), aftertaste (flavor), and grainy (texture).

2.5. Data Analyses

The temporal dominance of sensations test was evaluated using a specific test in Sensomaker and presented as a graph (time vs. dominance rate).

2.6. Ethical Aspects

This study was approved by the Research Ethics Committee of the Federal University of Goias, Goias, Brazil, under CAAE n.60681922.9.0000.5083. All procedures performed adhered to Resolution CNS 466/12, observing respect for human dignity, rights, and protection of life for research participants. All persons involved gave their informed consent before their inclusion in the study.

3. Results

3.1. Sensory Description Terms of Juçara Pulp

The descriptors selected by the trained panel were mostly related to aroma, taste, and flavor attributes, followed by appearance and texture (

Table 1. Attributes, definition, and references used in the descriptive test for juçara pulp.

Attribute	Definition	Reference
Appearance
Fluid	Easy to drain, no resistance, very watery	Strong: juçara pulp diluted (1:3) and filtered Weak: juçara pulp beaten with Nanica banana and frozen
Purple	Dark reddish-purple color characteristic of anthocyanin pigments	Strong: natural juçara pulp with purple additives Weak: diluted dehydrated juçara pulp (1:10)
Velvety	Smooth, soft, and silky texture	Strong: dehydrated juçara pulp blended with melted white chocolate (1:1) Weak: dehydrated juçara pulp mixed with water (1:2)
Aroma
Earthy	Like or relating to earth	Strong: beetroot solution and filtered mixed with water (1:2) Weak: grape nectar
Woody	Like wood, bark, striking	Perceptible: juçara pulp diluted in Carménère grape wine with notes of French oak (1:1) Imperceptible: whole grape juice
Petrichor	The smell produced when rain falls on dry ground	Perceptible: fresh açaí pulp (1:1) Imperceptible: grape nectar
Senescent	The smell produced by very ripe fruit denotes rotting	Strong: dehydrated juçara pulp mixed (45 g) with alcohol vinegar (100 mL) and dry red wine (100 mL) Weak: diluted dehydrated juçara pulp (1:10)
Flavor
Oily	Film formation in the mouth, similar to oil	Strong: dehydrated juçara pulp (45 g) mixed with butter (20 g) and white chocolate (40 g) Weak: whole grape juice
Earthy	Aromatic association with the earth; a taste of earth	Strong: pulp of juçara mixed with beetroot (2:1) Weak: grape juice diluted in filtered water (2:1)
Sweet	With a high sense of sweetness	Strong: dehydrated juçara pulp diluted in water (1:2) and mixed with sugar (60 g/L) Weak: dehydrated juçara pulp diluted (1:2) with salt (1 g/L)
Aftertaste	Taste that a particular food leaves in your mouth when you have swallowed it	Strong: juçara pulp mixed with water (1:2) with the addition of cabernet sauvignon wine with an aftertaste 100 mL/L Weak: in natural diluted juçara pulp (1:10)
Texture
Grainy	Presence of particles perceptible in mouth	Strong: juçara pulp with the addition of mixed nuts 40 g/L Weak: dehydrated juçara pulp diluted (1:2) and sifted

). The appearance of components were associated with color, matter phase, and perception of softness. The aroma had natural references, such as earth, wood, and senescent fruits. The taste was described as sweet, and the flavor as fatty and earthy, with a notable aftertaste. The texture was described as granular (Table 1).

3.2. Uncommon Terms

The panel generated 60 terms to describe juçara pulp. However, only 18 terms were cited by more than 1 person and 12 were chosen to describe the juçara pulp by the trained panel; almost identical definitions for each term were created by individual panelists.

Regarding the uncommon terms n = 60, we attributed these to the complexity of the sample, a lack of previous experience with juçara pulp in daily life, and because each person has different personal experiences of food. Regarding the color, some complex descriptions of purple, red, and brown were produced. In fact, juçara pulp exhibits a complex mix of three colors, especially if you mix it with other ingredients such as sugar and water. In addition, it was necessary to remove some redundant terms; velvet was chosen and aerated, creamy, and puree were removed. Some terms regarding appearance were also removed after panel discussions and allocated to texture.

For the texture terms, redundant terms were removed; grainy was chosen and sandy and fibrous were removed. Terms that were allocated to other attributes were removed, such as liquid, velvety, and creamy, which are related to appearance. Other terms to describe the pulp were not agreed upon by the panel, so they were excluded.

The uncommon flavor terms highlight the particular sensations experienced by each person with the same product. The list of flavors contains umami, salt, sour, rancid, and astringent terms. However, the panel, after discussion, agreed that these terms refer to a particular sensation of the product. The list of uncommon aroma terms shows the same was true for the flavor, revealing the particularities of the panel with respect to food; the list contains olive aroma and jatoba fruit aroma. Some attributes were considered too abstract, such as natural aroma and old aroma, and they were removed after a panel discussion.

3.3. Temporal Dominance of Sensations (TDS)

The TDS test shows how different sensations dominate over time. The “Fluid” sensation (red) was quite dominant at the beginning and then decreased (Figure 1). Some sensations, such as “Fluid” and “Grainy” (yellow), exhibit dominant peaks, indicating that they were the most dominant sensations during certain periods. Sensations that exceed the significance line are statistically significant.

In the first 20 s, the fluid sensation was the most dominant. Between 20 and 50 s, grainy started to appear, and after 50 s, grainy exhibited a significant peak, followed by other sensations that emerge and fade.

4. Discussion

All participants reported either an extreme açaí or a very extreme açaí taste, which is important because of the similarity between commercial açaí and juçara pulps [4]. In addition, juçara was not commonly consumed by the panelists. Therefore, acceptance of juçara possibly represented familiarity with the sensory characteristics of açaí pulp.

A total of 8 panelists were included in the trained panel, which is valid according to the expected number of tasters (from 8 to 25 testers) for descriptive tests [21]. The number of panelists was similar to those used in a study by Silva et al. [9], who also sensorially analyzed juçara pulp using 7 trained individuals. Studies carried out with other berries used a trained panel of 8 to 12 panelists [22,23].

It is important to consider that color is one of the main sensory characteristics used in the evaluation of a food product. Juçara’s purple color is due to the high content of anthocyanins such as cyanidins [5,24]. In addition, the purple color is connected to a component which is “similar to acai”, showing the similarity between these pulps in appearance. Augusto et al. [25] describe the atomization method as a possible cause of color degradation; however, in this study, after atomization and rehydration, the juçara pulp was still a reddish-purple color.

The “Earthy” component is common to aroma and flavor attributes. This result demonstrated the relationship between the aroma and flavor of juçara pulp [26]. Therefore, we can say that the earthy flavor of the juçara pulp is part of the sui generis flavor of the pulp.

Juçara’s flavor is a complex mixture of sweet and fatty, justified by its chemical composition. The pulp is rich in lipid compounds, at an average of 28.36% (3.17–46.6%) [27]. The perceived sweetness is probably the result of the combination of natural sugars in the fruit with added sugars (around 4%). But it is important to consider the natural sweetness of the fruit; after all, the added sugar content was low. The use of sugar can be explained as an attempt to achieve a composition close to that of commercial drinks, juices, and creams, which are, in general, sweetened. Silva et al. [9] used a similar protocol based on the same motivation. In their study, the authors evaluated the effect of pasteurization followed by storage under different conditions on the sensory attributes of frozen juçara pulp.

The grainy term indicated in the texture is explained by the fiber content present in the pulp. According to Vannuchi et al. [27], the average fiber value of juçara pulp is 27.7%. In addition, in the pulp extraction process described by Schulz et al. [2], just one sieving step with a common sieve was used. Thus, the grainy characteristic may be due to the excess fibers that remain in the pulp.

In the temporal dominance of sensations test, the dominance of the aftertaste that appears between 30 and 40 s after consumption of the sample is significant. An aftertaste is a gustatory–olfactory sensation left by food after consumption. It is known that there can be positive and negative aftertastes; in this case, it was not properly established by consumers which type of aftertaste they were referring to. Despite this, they linked this aftertaste with the pulp fat.

Limitations and Strengths of the Study

This is the first study that creates a primary lexical term and evaluates the dominance of sensations in juçara pulp. The study used a trained panel, familiar with sensory analysis techniques. The limitation of this study is that, as a pilot, we used just one sample and added sugar to it. On the one hand, this allowed us to achieve smoothness closer to that of commercial products. Another possible limitation is the homogeneous age range and lack of demographic diversity of the panel participants. We highlight for future studies the necessity to incorporate the views of untrained panelists, thereby making the study’s findings more applicable to the general population.

5. Conclusions

Personal experiences and references can interfere in the evaluation of food. However, a trained panel can remove this type of bias. According to the results of this study, juçara can be considered a product different from açai, characterized by a unique flavor, since this panel was familiar to açai. The approximate composition of the juçara fruit is revealed, consisting of high fat and fiber contents linked to its sensorial properties.