Physicochemical properties, fatty acids, phenolic compounds, and mineral contents of 12 Serbia regional and commercial almond cultivars

Almond (Prunus dulcis) Bagasse as a Source of Bioactive Compounds with Antioxidant Properties: An In Vitro Assessment

The presence of components of nutritional interest makes fresh almond bagasse an interesting by-product for obtaining functional ingredients. Stabilization through a dehydration process is an interesting option for its integral use, ensuring its conservation and management. Subsequently, it can be turned into powder, facilitating its use as an ingredient. The aim of this paper was to determine the effects of hot air drying at 60 and 70 °C and lyophilization on the release of phenolic components and antiradical capacity in in vitro gastrointestinal digestion and colonic fermentation, as well as on growing microbiota composition by applying high throughput sequencing. The novelty of this study lies in this holistic approach; considering both technological and physiological aspects related to gastrointestinal digestion and colonic fermentation will provide the best conditions for functional foods. The results obtained showed that lyophilization provides a powder with a total phenol content and antiradical capacity higher than hot air drying. Furthermore, in dehydrated samples, both in vitro digestion and colonic fermentation revealed a phenol content and anti-radical capacity superior to those existing in undigested products. In addition, after colonic fermentation, beneficial bacteria species have been identified. Obtaining powders from almond bagasse is presented as an interesting opportunity for the valorization of this by-product.

In vitro digestion and colonic fermentation of phenolic compounds and their bioaccessibility from raw and roasted nut kernels

Roasting and digestion affect nut kernel phenolic compounds' bioaccessibility and bioactivity. In this study, three types of raw and commercially roasted nut kernels (almonds, cashews, and walnuts) were treated by in vitro digestion and colonic fermentation. The objective was to analyze the effect of roasting on their phenolic content, associated antioxidant potential, bioaccessibility, and short chain fatty acid (SCFA) synthesis altering. Among these, raw and roasted walnuts performed best, with significantly higher total phenolic content (TPC), total flavonoid content (TFC), free radical scavenging (2,2'-diphenyl-1-picrylhydrazyl (DPPH) assay) values, and ferric reducing antioxidant power (FRAP) values after completing gastrointestinal digestion. With the exception of cashews, roasting had no significant effect on antioxidant capacity during digestion from oral to small intestinal phase. Almonds showed the highest DPPH values after 16-hour colonic fermentation, reaching above 7.60 mg TE per g. Roasting had a positive effect on the free radical savagery capacity of walnuts within 16-24 hours of fecal fermentation. Significant differences were found in the bioaccessibility of individual compounds in raw and roasted nuts. As for almond and walnut, roasting increases the release and breakdown of phenolic compounds during colonic fermentation and have a positive impact on the bioaccessibility of specific phenolic compounds. The colonic bioaccessibility of most phenolic compounds was the highest. Due to heat polysaccharide breakdown, the total SCFAs produced were limited up to 0.03 mM. Raw almonds produced the most SCFAs at 16-hour fermentation and illustrated more benefits to gut health.

Effects of Geographic Region and Cultivar on Fatty Acid Profile and Thermal Stability of Zanthoxylum bungeanum Seed Oil

Fatty acid profile and thermal stability of 7 varieties zanthoxylum bungeanum (GZF, GDJ, CJJ, SHY, SMN, SJY, GTS) seed oils (ZBO) were studied. Fatty acid profile, thermal stability were determined using gas chromatography equipped with flame ionization detector (GC-FID) and thermogravimetry analysis (TGA), respectively. Chemical properties, total phenolics and antioxidant activities of ZBO were determined as well. Palmitoleic acid and oleic acid (OA) were the dominant fatty acids, the ratio of ω-6/ω-3 polyunsaturated fatty acids (PUFA) of ZBO ranged from 0.66 ± 0.01 to 1.17 ± 0.01, seven varieties ZBO showed a higher thermal stability, with the 50% mass loss temperature ranged from 397.35 ± 4.02°C to 412.50 ± 2.35°C, GZF seed oil showed a balance fatty acid profile, the ratio of ω-6/ω-3 PUFA was 0.90 ± 0.01, GDJ seed oil showed a higher thermal stability, which the 50% mass loss temperature was 412.50 ± 2.35°C. These results suggested that fatty acid profile and thermal stability of ZBO were affected by cultivars and geographic region, and it may serve as a functional dietary oil.

Study of Phenolic Compounds and Antioxidant Capacity of Spanish Almonds

Phenolic compounds have an important influence on fruit and nut quality. Almonds have been shown to be rich sources of phenolic compounds, which possess health-beneficial properties. The objectives of the study were to optimize an extraction method to determine the total amount of polyphenols, flavonoids and proanthocyanidins as well as the antioxidant capacity. In addition, the same extract was used for the identification and quantification of flavonoids by HPLC. The study was conducted on 11 Spanish almond genotypes. The results highlight the differences in the content of antioxidants, which add value to the quality of the fruit. It has been shown that genotype may strongly influence antioxidant capacity and total phenolic compounds. In this work, the almonds with higher results were (Belona, Guara and Vialfas) varieties.