Physical–chemical changes in early dwarf cashew pseudofruits during development and maturation

Transcriptome profiling of cashew apples (Anacardium occidentale) genotypes reveals specific genes linked to firmness and color during pseudofruit development

We found 34 and 71 key genes potentially involved in flavonoid biosynthesis and cell wall disassembly, respectively, which could be associated with specific peel coloration and softening of each genotype. Cashew apple (Anacardium occidentale) has a great economic importance worldwide due to its high nutritional value, peculiar flavor and aroma. During ripening, the peduncle develops different peel color and becomes quickly fragile due to its oversoftening, impacting its consumers' acceptance. In view of this, the understanding about its transcriptional dynamics throughout ripening is imperative. In this study, we performed a transcriptome sequencing of two cashew apple genotypes (CCP 76 and BRS 265), presenting different firmness and color peel, in the immature and ripe stages. Comparative transcriptome analysis between immature and ripe cashew apple revealed 4374 and 3266 differentially expressed genes (DEGs) to CCP 76 and BRS 265 genotypes, respectively. These genes included 71 and 34 GDEs involved in the cell wall disassembly and flavonoid biosynthesis, respectively, which could be associated with firmness loss and anthocyanin accumulation during cashew apple development. Then, softer peduncle of CCP 76 could be justified by down-regulated EXP and up-regulation of genes involved in pectin degradation (PG, PL and PAE) and in cell wall biosynthesis. Moreover, genes related to flavonoid biosynthesis (PAL, C4H and CHS) could be associated with early high accumulation of anthocyanin in red-peel peduncle of BRS 265. Finally, expression patterns of the selected genes were tested by real-time quantitative PCR (qRT-PCR), and the qRT-PCR results were consistent with transcriptome data. The information generated in this work will provide insights into transcriptome responses to cashew apple ripening and hence, it will be helpful for cashew breeding programs aimed at developing genotypes with improved quality traits.

Chemometric analysis of the volatile profile in peduncles of cashew clones and its correlation with sensory attributes

Cashew apple, the hypertrophied peduncle of cashew nut, is a functional food with a high antioxidant activity and with good characteristics for juice industrialization and fresh consumption such as fleshy pulp, soft peel, without seeds, and exotic flavor. However, it is still poorly used or totally wasted. For this reason, the quality of cashew apples has received more attention from the Brazilian breeding program to maximize their uses. In this study, the volatile compound profiles of peduncles of seven cashew clones and their relation to the aroma and flavor differences were investigated. Nine trained panelists evaluated the cashew apples by descriptive analysis. After the standardization of headspace solid-phase microextraction (HS-SPME) extraction and chromatographic conditions, the volatile organic compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 48 compounds were identified with esters being the major chemical class, both in number of compounds and chromatographic peak area. The targeted and untargeted principal component analysis (PCA) analyses showed complementary and corroborative results from the cashew apple volatile composition based on genotype. The partial least squares (PLS) modeling revealed the high correlation of the unpleasant sensory attributes with the PRO805 and CAPI17 clones; sweet taste and sweet odor with the CCP76 clone; and cashew aroma/cashew flavor with the EMBRAPA51, HAC276, PRO555, and SLC12.20 clones. The correlation between the most relevant volatile organic compounds (VOC) for cashew apples and the sensory descriptors showed that the compounds methyl butanoate, methyl 3-methylbutanoate, ethyl 2-methylbutanoate, methyl 2-butenoate, methyl 3-methylpentanoate, 3-carene, methyl (E)-2-methyl-2-butenoate, ethyl 4-methylpentanoate, 2-hexenal, butyl 3-methylbutanoate, butyl pentanoate, and 3-methyl butanoic acid were important to explain differences in the characteristic fruit aroma and flavor of cashew apples among the studied clones. PRACTICAL APPLICATION: Cashew crops have been developed by using improved clones with increased nut productivity and resistance to diseases. The Brazilian genetic improvement program is also seeking to improve the quality of peduncles to maximize their use and prevent their destination as agricultural waste. In this study, the volatile profile of peduncles of seven cashew clones was determined and its correlation with the differences in their aroma and flavor attributes established. The results will provide important information about the potential of the new materials for fresh consumption and for the manufacturing of cashew juices, in addition to be used by breeders interested in improving the aroma of the fruit.

Evaluation of cooking methods on the bioactive compounds of cashew apple fibre and its application in plant-based foods

Plant co-products currently represent an attractive alternative to the food industry, especially to the growing market of development low-fat products. Among the co-products resulting from tropical fruits' processing, the cashew apple's fibre presents unusual nutritional and sensory characteristics. In several food preparations could use it as an ingredient. In this work, the bioactive compounds of both artisanal and industrialized cashew apple fibre were studied and the influence of the different cooking methods on their bioactive content, and the acceptance and sensory preference of products new plants-based products formulated. It was observed that both artisanal and industrial cashew apple fibres presented a rich composition in the bioactive compounds, especially regarding the content of ascorbic acid found in artisanal (147.8 mg.100g-1) and carotenoids in industrialized fibre (1.87 mg 100 g-1), which resulted in a higher antioxidant activity for both samples in each method evaluated. Frying (180 °C/3 min) and cooking in a combination oven (98 °C/10 min) exhibited higher averages regarding the retention of the bioactive compounds in the fibres, resulting in a higher antioxidant activity for the products processed by these methods. In contrast, it was boiling processing (100 °C/18min) leads to leach of water-soluble biocompounds and, consequently, their products presented a reduced antioxidant activity. The cashew apple "paçoca" and "meatballs" were judged in terms of their attributes (appearance, aroma, taste, overall impression) and buy intention. In general, the average of these results indicated a high sensorial acceptance and a partial possibility in their purchase of these products. The cashew apple fibres are a source of nutrients. Its incorporation in culinary preparations can be a friendly way to avoid waste and promote new food products.

Anti-inflammatory and wound healing potential of cashew apple juice (Anacardium occidentale L.) in mice

Cashew apple is a tropical pseudofruit consumed as juice due to its excellent nutritional and sensory properties. In spite of being well known for its important antioxidant properties, the cashew apple has not been thoroughly investigated for its therapeutic potential. Thereby, this study evaluated the antioxidant capacity, anti-inflammatory, and wound-healing activities of cashew apple juice. Juices from ripe and immature cashew apples were analyzed for antioxidant, anti-inflammatory, and wound-healing properties. Those were evaluated in murine models of xylene-induced ear edema and wound excision. Swiss mice were treated with cashew juice by gavage. Edema thickness was measured and skin lesions were analyzed by planimetry and histology. Both antioxidant content and total antioxidant activity were higher in ripe cashew apple juice (RCAJ) than in unripe cashew apple juice (UNCAJ). The UNCAJ presented the main anti-inflammatory activity by a significant inhibition of ear edema (66.5%) when compared to RCAJ (10%). Moreover, UNCAJ also showed the best result for wound contraction (86.31%) compared to RCAJ (67.54%). Despite of higher antioxidant capacity, RCAJ did not promote better anti-inflammatory, and healing responses, which may be explained by the fact that treatment increased antioxidants level leading to a redox "imbalance" turning down the inflammatory response modulation exerted by reactive oxygen species (ROS). The results suggest that UNCAJ presents a greater therapeutic activity due to a synergistic effect of its phytochemical components, which improve the immunological mechanisms as well as an optimal balance between ROS and antioxidants leading to a better wound healing process.