1. Introduction
Brazil has the most diversified flora in the world, with approximately 33,161 plant species, corresponding to 26.5% of the total number of species currently known [
1]. In this context, biodiversity is associated with a wide variety of natural compounds, with a wide possibility of developing new drugs, agrochemicals, fragrances, cosmetics, ingredients, and food supplements, providing a catalog of opportunities for biotechnological innovation and an unbeatable competitive advantage [
2,
3]. Nowadays, modeling the strict linkage between environmental, ecological and food resources in the biodiversity and health benefits perspectives represent great challenges [
4,
5].
Bacuri (
Platonia insignis) is a tree species of the
Clusiaceae family, which encompasses approximately 1000 species belonging to 47 genera, although bacuri is a monotype. Plantations occur in the wild, and propagation occurs through seeds or sprouts that arise spontaneously in the roots of adult plants [
6,
7]. The Amazon is its original area, although it also has a distribution along the Atlantic coast, going from the Guianas to the mid-northern region of Brazil. The area of greatest concentration is in the estuary of the Amazon River, and the largest production and marketing centers are in the states of Pará, Maranhão, and Piauí [
8,
9].
The fruits are usually collected through the extractive system, with the use of trees that already exist in the producing regions. However, besides the extractive system, at least two more types of systems are known: regrowth management and planting systems. Regrowth management is a process of improvement of simple extractivism, in which more favorable conditions are created for bacuri trees by using low-cost technologies. The system of planting saplings, seeds, and grafting, which is considered the most recent and promising, allows faster production of fruits while maintaining the preservation of the system [
10].
Regarding the botanical aspects, the fruit is of berry type and presents shapes that can vary from pear-shaped to rounded [
11] and may also present other intermediate types. However, in the same tree, the shape of the fruits is uniform, which demonstrates that the bacuri tree has genetically well-fixed characters [
12]. The length of the fruit is 7–15 cm, and the diameter is 5–15 cm, with a weight that usually varies from 200 to 500 g [
13], although some types can reach a weight of more than 1000 g [
11]. The shell has a very thick structure (1–3 cm), responsible for the largest volume of the fruit, with a color that can vary from green to yellow-citrine and reddish-brown. On the other hand, the pulp has a creamy-white color and an essentially floral flavor with fruity notes [
14,
15].
Bacuri (
Figure 1) is a fruit with very different characteristics from a physiological perspective. It presents a non-climacteric breathing pattern at all stages of maturation from the third day of harvest (ambient conditions with a relative humidity of 75.1% and 25.2 °C) [
16,
17]. Although there may still be a slight softening and color change when harvested before the sweet spot, no considerable improvement in their sensory and nutritional characteristics can be observed [
14].
The fruits are predominantly provided with seeds with an ellipsoidal shape, with an average weight of 24.4 g. The intensity of the angularities depends on the number of seeds that form in the fruit [
18]. Although seeded bacuri is the most commonly found type, in 1970, seedless bacuri, a variety initially found on the island of Marajó, was reported [
11]. The phenomenon of parthenocarpy occurs when none of the ovules located in one or more locules is converted into seed. It is assumed that the fraction of the pulp represented by the parthenocarpic segments is tastier, mainly due to its lower acidity. However, more studies are still needed to prove it [
19].
Although seedless fruits present themselves as a viable alternative for industrial application in the food sector, recently, studies for the use of extracts obtained from seeds have gained emphasis and visibility, as well as other parts of the fruit and the palm, which diverse biological activities are being reported promising [
20].
This study aimed to gather data on the species Platonia insigns Mart. through an integrative review of agronomic, nutritional, physical–chemical characteristics and a technological prospection about its applications.
2. Research Methodology and Selection Criteria
An integrative review concerning bacuri (
Platonia insignis Mart.) was carried out by searching for publications in which the fruit, parts of the fruit, or the palm tree were used. The prospection was based on scientific articles and patent applications in several bacuri/bacuri tree application areas. The words “
Platonia insignis” and “bacuri” were used as descriptors when searching scientific articles and patents. A systematic search for articles was carried out in the Capes Journal Portal, Science Direct, Web of Science, and PubMed databases. The search strategy, period, and steps followed for database analysis are shown in
Supplementary Figure S1.
The documents generated in the research underwent the first screening according to the title and keywords contained in the publication. Then, they were analyzed according to the following inclusion criteria: abstracts and full texts that report the various applications of Platonia insignis, including its botanical and nutritional characteristics, therapeutic, nutraceutical, cosmetic, food, and industrial applications.
The research used the databases made available by the National Institute of Industrial Property (INPI), the United States Patent and Trademark Office (USPTO), the European Patent Office (EPO), and the World Property Organization. Intellectual (WIPO) to search for patents. The combinations of the words “bacuri” and “Platonia insignis” were used, and then, in different searches, the terms “bacuri” and later “Platonia insignis” in the search field for the title of the patents.
3. Results and Discussion
Supplementary Figure S2 reports the quantitative results of research and analysis of publications and patents. In the first step, the search accounted for a total of 443 documents initially distributed as follows: Capes Periodicals (176), Science Direct (94), Web of Science (113), and PubMed (60). In a second step, the texts were screened according to the scope of the work, leaving a total of 106 publications covering the period from 1945 to 2021 at the end of the selection. Regarding patent applications, the research found 12 deposits using bacuri. However, two were excluded because they used the term for the species
Attalea phalerata Mart. From the 10 valid registrations, 9 are registered at the INPI and 1 at the WIPO via PCT. The WIPO platform also provides information on INPI records, considered in the phase of excluding duplicate documents. No records were found in the other patent databases. The distribution of scientific articles related to
Platonia insignis by year of publication is reported in
Supplementary Figure S3. It is possible to verify that research related to bacuri intensified from 2018 to 2021. This period corresponds to 50% of published patents. Major study focus areas for
Platonia insignis Mart. is reported in
Supplementary Figure S4. Studies related to agronomic aspects of bacuri are still predominant (31 documents). These focus mainly on care and management for cultivation, reproduction strategies, and, as a highlight recently, studies related to species maintenance and biodiversity conservation.
Another highlight has been the search to elucidate the chemical compounds responsible for the reported biological effects. In the last 10 years, research has sought to understand the biological effects of these compounds on the body or to elucidate compounds that have not yet been identified and their mechanisms of action, which opens the way for further studies. The other highlighted areas are biomedicine, science, and technology, among others.
3.1. Bacuri Composition: Pulp Characteristics and Applications
Bacuri is one of the most prominent Amazonian fruits. Its organoleptic characteristics allowed its success both in the group of fruits for in natura consumption and industrial use [
21]. The pulp, in addition to the nutritional aspects, presents properties that allow its wide application in the industry, mainly for the production of juices, jellies, and ice creams. [
6].
The centesimal composition, composition of minerals, vitamins, and amino acids, and physicochemical characteristics are reported of bacuri pulp (
Platonia insignis Mart.) are reported in
Table 1,
Table 2 and
Table 3. In quantitative terms, carbohydrates are the main macronutrients that compose the pulp and are almost entirely responsible for energy values (
Table 1). Among the total sugars, sucrose comprises 18.5%, while glucose and fructose comprise 15.5% and 15.6%, respectively [
22].
Previous studies have reported the wide variation in the range of values referring to physicochemical parameters of bacuri pulp, such as soluble solids, pH, and acidity, among others (
Table 3), mainly related to the place of origin of the fruit, genotype, cultivation practices, maturation stage, harvest time, storage conditions and post-harvest changes [
24]. In the food industry, the evaluation of these physico-chemical parameters is essential to define the possibilities and ways of pulp application. For example, fruits with higher acidity are less sweet, and therefore they are used mainly for the elaboration of products whose final formulations usually result in products with higher added sugars, such as jams and jellies [
6,
16].
3.2. Bacuri Shell
The shell constitutes about 70% of the total volume of the fruit. Its composition has high water content, representing more than 70% of its constitution. Even with a low lipid content, oleic, linoleic, stearic, and palmitic acids are constituents of this matrix (
Table 4).
Although rich in pectin (5.0%) and valuable in the food industry with gelling and stabilizing paper, the shell generated after pulping is commonly discarded (
Table 4). That is mainly due to the presence of a resinous substance with a bitter taste in its constitution, called resinotrol, which elimination without the concomitant loss of aroma and flavor requires the application of specific technologies, which increases the costs of processing [
6,
8]. It is still a challenge for the industry to develop techniques that enable the use of the shell for this purpose.
3.3. Bacuri Seeds
Bacuri seeds are characterized by a high content of lipids and being rich in dietary fiber. Lipids constitute, on average, 31.88% of its composition, while moisture, proteins, and fixed mineral residue contribute with 31.91%, 3.15%, and 1.03%, respectively. From the 32.02% carbohydrate content, dietary fiber represents around 19.57% [
29]. Previously considered just waste, the seeds began to attract attention for their constitution of lipids and biologically active compounds. The oil extracted from the seed, commonly called bacuri butter, although still used on a small scale, already appears as a promising possibility for better use of the fruit [
30,
31].
The bacuri seed butter has an average of 64% saturated fatty acids, 34% monounsaturated, and 2% polyunsaturated [
32]. Although there are quite a few old reports on the use of oil extracted from the seeds of
Platonia insignis in the treatment of various skin diseases and diarrhea [
33], it is with the advancement in the studies on the chemical profile of its seeds that some gaps have begun to be filled (
Table 5).
The seed oil has 50–55% tripalmitin in its constitution, allied to the fatty acid content [
32]. This triglyceride, which originated from the acylation of the three hydroxyl groups of glycerol by palmitic acid, has humectant characteristics, providing high penetration into the skin with wound healing properties [
34,
35]. According to Pesce (2009) [
36], the extraction of this oil presents many difficulties, mainly related to extraction methods due to the high-fat percentage. However, currently, there is an expectation of using processes in which it is possible to obtain a resin-free fat with a lighter color and more attractive sensory characteristics, which can be marketed at a higher price than the dark fat obtained by the extraction with presses.
Table 5.
Lipid composition of bacuri clarified butter obtained by pressing.
Table 5.
Lipid composition of bacuri clarified butter obtained by pressing.
Fatty Acids | Virgin | Clarified | References |
---|
Palmitic acid (C16:0) | 60% | 64% | [36,37] |
Oleic acid (C18:1) | 28% | 25.32% |
Palmitoleic acid (C16:1) | 7% | 6.27% |
Myristic acid (C14:0) | 2% | * |
Linoleic acid (C18:2) | 2% | 2.81% |
Lauric acid (C12:0) | 1% | * |
Stearic acid (C18:0) | 1% | 1.44% |
In terms of lipid composition, the products obtained by different extraction methods of bacuri butter are similar among them. According to Sabará et al. (2018) [
37], clarified butter has low levels of acidity and peroxide (
Table 6), which improves its performance, making it ideal for the development of cosmetic products for mature skins.
Due to its characteristics and lipid composition, the oil extracted from bacuri seed is of particular interest to the food industry. Furthermore, studies have shown that bacuri seed oil possesses an important healing activity and it can be used in the treatment of burns and wounds [
34,
38]. Moreover, recently, in vivo studies point to an important potential antioxidant and cardioprotective action [
39,
40].
3.4. Volatile Flavor Compounds
The exotic flavor and aroma of bacuri reflect an immense and interesting combination of volatile compounds such as terpenes, hydrocarbons, and, to a lesser extent, aldehydes [
41]. In some fruit species, a single substance can reflect the approximate flavor of a product, which is called an “impact compound” [
42]; however, concerning bacuri, what is observed is a complex coexistence of substances that provide unique aromatic characteristics to this fruit [
41].
Although the fruity note of bacuri is attributed to the presence of methyl hexanoate, it is currently known that linalool is the compound responsible for its more intense aroma and floral aroma [
43]. Initially, linalool and 2-heptanone were identified as the responsible for the characteristic aroma of the fruit, however, abundantly, other volatile compounds were later identified in bacuri pulp [
44], such as pyran and furan isomers of oxides resulting from linalool or hotrienol, 2,6-dimethyl-octa-3,7-dien-2,6-diol, α-terpineol, (E) and (Z)-2,6-dimethyl-octa- 2.7-dien-1,6-diol, methyl hexanoate and 2,6-dimethyl-octa-1,7-dien-3,6-diol (
Figure 2). These compounds can be formed either from precursors or through chemical rearrangement during heat treatment [
41]. An important point about aroma components involves the isomerism of these molecules. Optical isomers can, on the other hand, result in distinct aromatic notes. Although subtle chemical differences sometimes occur, these changes can strongly influence the biological effects of these compounds [
45]. Many of these compounds reported for bacuri can be found both in the pulp and fruit shell, suggesting that there is a transfer of flavor between the parts and, thus, giving the shell-seed structures an important synergistic relationship for the determination of these characteristics.
According to Boulanger et al. [
46], the identification of the presence of fatty acid esters, ethyl hexanoate, methyl octadecanoate, ethyl octadecanoate, and dimethyl ketones with an odd number of carbons, even in small amounts, is an essential indicator of the possible contribution of the metabolism of lipids in the biogenesis of bacuri aromatic compounds, which can be attested by the presence of important amounts of free fatty acids.
These characteristics have important value in the food industry in improving the sensory quality of food formulations. Nazaré et al. [
44] carried out the extraction by heating the aroma of the compounds from the bacuri shell and its application as a replacement for the pulp to give the natural yogurt the characteristic flavor of this fruit. The study concluded that the aroma of bacuri can replace, with numerous advantages, the use of pure or diluted pulp of this fruit in the manufacture of yogurt with this flavor.
Although considered one of the most straightforward techniques for extracting aromas from bacuri, heating in different pH ranges can result in changes in the conformation of these volatile compounds, which implies, for example, greater production of oxygenated terpenes. In addition, the processing of pulp by heat can affect these components, by demonstrating the importance of cataloging them to better understand the role of these compounds in technological terms and concerning their potential biological effects for better use [
41].
As an example, we have the 2,6-dimethyl oct-1-ene-3,7-diol that, when subjected to heating, results in the rearrangement that springs in linalool and R-terpineol, cited as one of the main components of bacuri aroma [
41].
3.5. Phytochemical Studies and Therapeutic Use of Bacuri
The available scientific literature expressively references different biological activities. Compounds extracted from the shell, seeds, flowers, and stem bark have shown that parts of the plant can be used as an alternative in the treatment of various diseases. Its potential as cardioprotective [
39,
47], vasorelaxant [
48], leishmanicidal [
49], immunomodulatory [
38], and for glycemic control [
50], among others, has been reported in a variety of studies (
Table 7). These effects are associated with the presence of compounds derived from terpenes, xanthones, and phenolics, in addition to saturated and unsaturated fatty acids, as can be seen in
Figure 3.
There is excellent potential for bacuri to develop drugs of natural origin, which have added economic value to the fruit, including the inedible parts of the plant [
52]. The antioxidant action observed in studies with different parts of the fruit and palm has been widely cited in publications dealing with biological effects. The recognized performance of bacuri components in inhibiting the formation of free radicals or in processes of interruption of cascade reactions is related to the reduction of the presence of radicals with harmful effects in the body, an effect attributed to the action of its bioactive compounds.
3.6. Technological Prospecting
In prospective research carried out in the main patent databases, it was possible to recover 10 deposits associated with
Platonia insignis published and, in effect, with claims for developing products or processes using different parts of the plant (
Figure 4). Of the total deposits, 9 were made in Brazil through the National Institute of Industrial Property (INPI) and 1 through the Patent Cooperation Treaty (PCT) (
Table 8).
The development of products in the cosmetic area ranges from extraction processes to claims about the application. For instance, there is a claim for a cosmetic composition comprising the genus
Platonia, in which the invention uses in its composition the butter obtained from the species
Platonia insignis associated with humectants and a cosmetically acceptable conductor [
70]. This deposit was initially made in Brazil and then via IPS, covering protection simultaneously in several countries, both in preparing the said composition and on the cosmetic use and method of application.
Another patent application refers to the elaboration and preparation with incubation of roots, shells, leaves, fruits, seeds, and oils produced from plants in the Amazon rainforest, including bacuri, which are selected, sterilized, and pasteurized to obtain a substance for use in cosmetics and formulations in general. There is still a claim in the cosmetics area about the creation of a lip cosmetic product made from bacuri butter to replace one of the main components of these products, beeswax [
74].
In the therapeutic field, there are three patent applications in effect. In one of them, the hexane extract of bacuri seeds was used as a base principle, presenting a function as an antiprotozoal agent, specifically referring to the leishmanicidal potential and its use in the formulation of the product(s) for the prevention and/or treatment of diseases caused by protozoa, mainly leishmania [
71].
The second application refers to obtaining antimicrobial phytotherapeutic for human use from the extract of
Platonia insignis leaves in different administration presentations, with microbicidal action against various bacteria and fungi of clinical interest for the isolated or associated treatment of infections caused by fungi and bacteria [
72].
The most recent patent in this field relates to the invention of an antimicrobial phytotherapeutic from the concentrated, lyophilized, and/or fractionated hydroalcoholic extract of the leaves of
Platonia insignis [
73]. The product, proposed in different administration presentations, presents microbicidal action against several bacteria and fungi of clinical interest for isolated treatment or associated with fungal and bacterial infections for human use. In addition, it is also indicated for treating diabetes
mellitus and other diseases related to glucose metabolism, inflammation, combating and decreasing pain, and acting on the immune system, providing an increase in organic responses.
Another three patents claiming the development and improvement of industrial processes through seeds and shells were also registered. One of these processes ranges from the extraction of bacuri seed oil to produce refined and clarified butter to its use as a chemical input to produce cosmetics, pharmaceuticals, and nutraceuticals, with a focus on skincare product formulations or scalp [
74].
The shells were used as raw material for obtaining the alcoholic extract to increase biodiesel’s oxidative stability to generate longer storage time and provide the possibility of meeting the minimum required by legislation based on additions of higher extract concentrations [
75].
Another invention, also within this line of thought, claims a product that, by mixing 50% of bacuri shell alcoholic extract with 50% of rosemary alcoholic extract, increases the oxidative stability of biodiesel, decreasing the rate constant of oxidation reaction, offering, therefore, a more extended storage period [
77].
During the research period, it is possible to observe that there are few patent applications related to
Platonia insignis (
Figure 5). Once advances in studies related to its properties continue, results for application in the most diverse areas will be increasingly viable and promising.
3.7. Use of Bacuri By-Products in the Production of Food Products
As a novelty in the food sector, research on using co-products from bacuri processing (shells and seeds) as ingredients in formulations has been reported with encouraging results (
Table 9).
Even in a very limited way, the fruit shell has been developed as a source of unconventional raw material in packaging pharmaceutical products for human consumption [
30]. On the other hand, the seed has been presented as a potential functional ingredient. In addition, using unconventional parts of fruits such as bacuri in formulations can, in addition to increasing the supply of ingredients, promote the valorization of natural resources.
4. Conclusions
This integrative analysis with bacuri (Platonia insignis) as the study target allows us to demonstrate that, although it is considered one of the most important fruits of Amazonian origin, studies are still scarce given the multiple properties concerned with this species. The prospection about its nutritional, sensorial, functional, and pharmacological characteristics shows that, although there is a wide opportunity for applications and high demand for possible applications about the findings related to the species, there are still few patents related to Platonia insignis. However, in the last few years, an increase in these numbers has been observed as new studies are conducted. The studies and innovative technologies developed for bacuri so far are focused primarily on the areas of therapeutic application, optimization of industrial processes focused mainly on the biodiesel area and the cosmetics sector, the latter being the most prominent due to the involvement of foreign companies interested in product lines from the Brazilian biodiversity, demonstrating the potential of the species in the national and international market. In addition, it is essential to highlight the importance of a systematic and frequent mapping of technological prospecting for the development, improvement, and economic viability of new industrial products or processes through the use of shells, seeds, flowers, stems, and leaves from bacuri, mainly in areas of great potential and still little explored, such as the area of food ingredients, where the research for an integral use of the fruit remains a challenge.