Selected nutrients and antinutrients in peanut cultivars harvested in Brazil

BACKGROUND

There are more than 30 peanut cultivars registered in Brazil. However, there are no published data about the content of nutrients and antinutrients even in the most commercially important ones. Therefore, our objective was to characterize commercial peanut cultivars harvested in Brazil by determining proximate and fatty acid composition and content of selected minerals and phytates, saponins and condensed tannins.

RESULTS

Significant variations were found among the cultivars for almost all studied nutrients, except Mg. Granoleico and IAC 505 were identified as high oleic. Results were compared with data from the Brazilian Food Composition Table (TACO) and, for this, percentage differences (D%) were calculated. Appreciable D% were found for proteins, lipids, ash, dietary fiber, almost all fatty acids (except 20:0) and almost all studied minerals (except zinc). Moreover, remarkable variations in content of antinutrients were observed. IAC Red Tatu had the highest content of saponins; IAC OL3 and IAC 886 had the highest amounts of phytates; and IAC 886 had the highest amounts of condensed tannins.

CONCLUSION

Results confirm the relevance of differentiating cultivars in the market and in national food composition tables and databases. Furthermore, some of these cultivars may be indicated for new use trends. © 2019 Society of Chemical Industry.

Opinion on the Hurdles and Potential Health Benefits in Value-Added Use of Plant Food Processing By-Products as Sources of Phenolic Compounds

Plant foods, their products and processing by-products are well recognized as important sources of phenolic compounds. Recent studies in this field have demonstrated that food processing by-products are often richer sources of bioactive compounds as compared with their original feedstock. However, their final application as a source of nutraceuticals and bioactives requires addressing certain hurdles and challenges. This review discusses recent knowledge advances in the use of plant food processing by-products as sources of phenolic compounds with special attention to the role of genetics on the distribution and biosynthesis of plant phenolics, as well as their profiling and screening, potential health benefits, and safety issues. The potentialities in health improvement from food phenolics in animal models and in humans is well substantiated, however, considering the emerging market of plant food by-products as potential sources of phenolic bioactives, more research in humans is deemed necessary.

Sacha inchi seeds from sub-tropical cultivation: effects of roasting on antinutrients, antioxidant capacity and oxidative stability

Due to the strong bitter taste, sacha inchi seeds are usually consumed after roasting, which also contributes to the elimination of antinutrients. Sacha inchi plants fully adapted to cultivation under sub-tropical climate conditions were produced in southeastern Brazil. Our main goal was to evaluate the effect of dry heating (roasting) on the antinutrient content of these seeds. We also investigated the effects of the applied roasting treatments on the antioxidant activity, proximate composition and oxidative stability of the seeds. To the best of our knowledge, this is the first report on antinutrients of sacha inchi seeds cultivated under sub-tropical conditions, outside their native tropical environment. Except for saponins, which are not heat-labile compounds, the contents of all assessed antinutrients continually reduced with the increase in roasting temperature. Roasting improved antioxidant activity and phenolic content in the seeds at the highest temperature. Oxidation changes occurred in the seed oil, and they increased with temperature. However, maximum peroxide value was within the acceptable consumption limits. As a conclusion, roasting treatments can be applied to minimize the antinutrient potential in sacha inchi seeds. Knowledge on the composition and proper processing of sacha inchi cultivated under sub-tropical conditions may support future efforts focused on the development of new production areas.

Phenolic acids and flavonoids of peanut by-products: Antioxidant capacity and antimicrobial effects

Peanut skin (PS) and meal from dry-blanched peanuts (MDBP) were evaluated as sources of phenolic compounds. PS rendered the highest total phenolic content, antioxidant capacity towards ABTS radical cation, DPPH and hydroxyl radicals as well as reducing power. Phenolic acids were present in PS and MDBP whereas proanthocyanidins and monomeric flavonoids were found only in PS as identified by HPLC-DAD-ESI-MSⁿ. Procyanidin-rich extracts prevented oxidation in non-irradiated and gamma-irradiated fish model system. Both extracts inhibited the growth of gram-positive (Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Geobacillus stearothermophilus) and gram-negative bacteria (Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli). Regardless of the strain, phenolic acid-rich extracts showed the lowest minimum inhibitory capacity (MIC); therefore presenting higher antibacterial effect. The MIC of phenolic acid-rich extracts (24-49μgphenolics/mL) was higher but comparable to Ampicillin (10μg/mL). Thus, phenolics in PS and MDBP may serve as antioxidants and antimicrobial compounds.

Enzyme-assisted extraction of phenolics from winemaking by-products: Antioxidant potential and inhibition of alpha-glucosidase and lipase activities

Phenolics in food and agricultural processing by-products exist in the soluble and insoluble-bound forms. The ability of selected enzymes in improving the extraction of insoluble-bound phenolics from the starting material (experiment I) or the residues containing insoluble-bound phenolics (experiment II) were evaluated. Pronase and Viscozyme improved the extraction of insoluble-bound phenolics as evaluated by total phenolic content, antioxidant potential as determined by ABTS and DPPH assays, and hydroxyl radical scavenging capacity, reducing power as well as evaluation of inhibition of alpha-glucosidase and lipase activities. Viscozyme released higher amounts of gallic acid, catechin, and prodelphinidin dimer A compared to Pronase treatment. Furthermore, p-coumaric and caffeic acids, as well as procyanidin dimer B, were extracted with Viscozyme but not with Pronase treatment. Solubility plays an important role in the bioavailability of phenolic compounds, hence this study may assist in better exploitation of phenolics from winemaking by-products as functional food ingredients and/or supplements.

Low molecular weight phenolics of grape juice and winemaking byproducts: antioxidant activities and inhibition of oxidation of human low-density lipoprotein cholesterol and DNA strand breakage

Bioactive compounds belonging to phenolic acids, flavonoids, and proanthocyanidins of grape juice and winemaking byproducts were identified and quantified by HPLC-DAD-ESI-MS(n). The concentration of phenolic compounds in different grape cultivars was in the order Tempranillo > Cora > Syrah > Isabel. The insoluble-bound fraction was most prominent, contributing 63 and 79% to the total for Isabel and Tempranillo, respectively. Juice-processing byproducts had a higher content of free than esterified phenolics, but the opposite was noted for winemaking byproducts. Insoluble-bound phenolics were up to 15 and 10 times more effective as antioxidants than those of free and esterified fractions, respectively, as evaluated by the DPPH, ABTS, and H2O2 scavenging activities and reducing power determinations. In general, insoluble-bound phenolics (100 ppm) were more effective in inhibiting copper-induced human LDL-cholesterol oxidation than free and esterified phenolics, exhibiting equal or higher efficacy than catechin. Phenolic extracts from all fractions inhibited peroxyl radical-induced DNA strand breakage. These findings shed further light for future studies and industrial application of grape byproducts, which may focus not only on the soluble phenolics but also on the insoluble-bound fraction.