Impact of encapsulated orange essential oil with ß-cyclodextrin on technological, digestibility, sensory properties of wheat cakes as well as Aspergillus flavus spoilage.

BACKGROUND: The majority of studies with essential oils in foods focus mainly on improving the shelf life of products; however, the present study goes further and demonstrates not only the effect of essential oil on conservation properties, but also the effect of free and encapsulated orange essential oil (OEO) on the technological, sensorial and digestibility properties of bakery products. RESULTS: OEO was encapsulated into ß-cyclodextrin (ß-CD) by inclusion complex formation (ß-CD/OEO 97.4% of encapsulation efficiency). OEO demonstrated in vitro antifungal activity against Aspergillus flavus (inhibition zone of 11.33 mm on mycelial growth). In situ antifungal activity against A. flavus confirmed that free OEO can effectively delay the fungal growth, unlike encapsulated OEO. Regarding texture profile and starch digestibility: cake with ß-CD/OEO showed lower hardness (31.64 N) and lower starch digestibility (69.10%) than cake with free OEO (44.30 N; 82.10%, respectively) and the addition of OEO (both free and encapsulated) decreased the adhesiveness of the cakes. Cake with free OEO showed a higher intensity of orange aroma, being preferred by 60% of panelists, whereas cake with ß-CD/OEO presented a very slight orange taste and aroma. CONCLUSION: The encapsulation of OEO into ß-CD improved the crumb texture of cakes and promoted a lower starch digestibility in the cakes. On the other hand, the encapsulation process was not effective under the conditions tested (OEO concentration and baking temperatures), compromising the action of the OEO as a natural flavoring and preservative agent. © 2021 Society of Chemical Industry.

Postharvest UV-C irradiation for fungal control and reduction of mycotoxins in brown, black, and red rice during long-term storage.

The formation of fungal colonies, mycotoxins, phenolic compounds, cooking quality and color properties were evaluated in freshly-harvested brown, black, and red rice grains and then subjected to ultraviolet radiation (UV-C) for 1 and 3 h. Assessments were made after 6 months of storage. The exposure of black and red rice at 1 h of UV-C was enough to decrease the presence of fungal colonies by 22% and 79%, respectively, without any changes in cooking and coloring properties. In brown rice, only 3 h of UV-C irradiation was able to reduce the formation of fungal colonies. The release of phenolic compounds associated with cell wall was observed only in black and red rice subjected to UV-C radiation. The levels of mycotoxins gradually decreased with the increase in the time of exposure to UV-C radiation, demonstrating UV-C irradiation to be an effective method in fungal control and reduction of mycotoxins in stored rice.

Fluidized-bed drying of black rice grains: Impact on cooking properties, in vitro starch digestibility, and bioaccessibility of phenolic compounds.

This study evaluated the influence of different fluidized-bed drying temperatures (20, 60, and 100 °C) on the cooking properties, in vitro starch digestibility, and phenolic bioaccessibility of black rice. The results indicated that the formation of fissures in the grains dried at or above 60 °C reduced the physical integrity of the grains after cooking, increasing the starch digestion and the rehydration ratio, and reduced the cooking time, the hardness and adhesiveness. Due to the higher digestibility of grains dried at higher temperatures, an increase in the bioaccessibility of ferulic acid, which was previously associated with the polysaccharides, was observed. Caffeic acid was the only phenolic compound whose levels decreased when the drying temperature increased. At high temperatures and in the gastric phase, cyanidin chalcones were formed due to the deglycosylation of cyanidin-3-O-glucoside. PRACTICAL APPLICATION: The results of this study provide information to the food industry about the effects of different fluidized-bed drying temperatures on the rice structure after cooking and that, consequently, affect the availability of bioactive compounds after digestion and the glycemic index of black rice.

Cake of brown, black and red rice: Influence of transglutaminase on technological properties, in vitro starch digestibility and phenolic compounds.

This study aimed to evaluate the influence of transglutaminase addition on the technological properties and in vitro starch digestibility of gluten-free cakes of brown, black, and red rice, as well as the effect of baking on the content of phenolic compounds. Transglutaminase addition exerted significant effect in the technological properties only in the brown rice cake, resulting in a decrease in crumb firmness and an increase in the specific volume. Red rice cakes treated with transglutaminase presented a lower glucose release rate (k) compared to cakes without the enzyme. Cakes from pigmented rice varieties had lower crumb firmness and k values than brown rice cakes. Baking reduced only the contents of ferulic and p-coumaric acids and significantly increased the extractability of hydroxybenzoic, caffeic, caftaric, and protocatechuic acids. However, the addition of the enzyme resulted in a slight decrease in the total phenolic content of the cakes.

Effects of drying temperature and long-term storage conditions on black rice phenolic compounds.

This study aimed to investigate the influence of drying temperatures (20, 40, 60, 80, and 100 °C) followed by 12 months-storage under normal-atmosphere (conventional), nitrogen-atmosphere, and vacuum-atmosphere on black rice phenolics. Increase in drying temperature reduced the total content of free-phenolics, free-flavonoids, and anthocyanins. An increase in bound phenolics extractability was observed at 60 and 80 °C, suggesting some extent of phenolics polymerization and complexation at these drying temperatures. The free fraction of ferulic, caffeic, p-coumaric, and gallic acids were the most thermally unstable compounds. After storage, no reductions were observed only for free caffeic and protocatechuic acids. For total flavonoids, an increase in the free fraction and reduction of the bound fraction were observed in the grains stored under conventional- and vacuum-atmosphere. A reduction of total phenolics occurred regardless of the storage condition. However, storage under nitrogen-atmosphere is the most recommendable condition for maintenance of phenolics in black rice.

Foliar Desiccators Glyphosate, Carfentrazone, and Paraquat Affect the Technological and Chemical Properties of Cowpea Grains.

The effects of the use of glyphosate (GLY), glyphosate plus carfentrazone (GLY/CAR), and paraquat (PAR) as plant desiccators on the technological and chemical properties of cowpea grains were investigated. All studied desiccants provided lower cooking time to freshly harvested cowpea. However, the coat color of PAR- and GLY/CAR-treated cowpea was reddish in comparison to the control treatment. Principal component analysis (PCA) from liquid chromatography-mass spectrometry (LC-MS) data sets showed a clear distinction among cowpea from the different treatments. Catechin-3-glucoside and epicatechin significantly contributed for discriminating GLY-treated cowpea, while citric acid was responsible for discriminating GLY/CAR-treated cowpea. Quercetin derivative and gluconic acid were responsible for discriminating control treatment. Residual glyphosate and paraquat content was higher than the maximum limits allowed by Codex Alimentarius and the European Union Commission. Improvements in the technological and chemical properties of cowpea may not be overlapped by the risks that those desiccants exhibit when exceeding the maximum limits of tolerance in food.