Effects of solid-state fermentation and extraction solvents on the antioxidant properties of lentils

The Browning Properties, Antioxidant Activity, and α-Glucosidase Inhibitory Improvement of Aged Oranges (Citrus sinensis)

Oranges contain many natural active chemicals, organic acids, and polysaccharides. Aging processing is commonly used to modify the color, quality, functional components, and stability of fruits. This study assesses the preparation of aging black oranges using various pre-treatments and solid fermentation. Oranges were aged for six weeks in fresh, non-blanching, blanching, and hot air-assisted aging cycle (AA) groups. The oranges' shrinkage ratio, color difference values, and soluble solids content changed significantly (p < 0.05). Principal component analysis indicated that aging fermentation treatment accelerated glycolysis and increased the ratio of reducing sugars. The enhanced browning can be associated with the oxidation of ascorbic acid (0.66-0.47 mg/g) and the formation of 5-hydroxymethylfurfural (5-HMF) (0.09 mg/g). Furthermore, the presence of free polyphenols led to an increase in the total polyphenol and total flavonoid content. It also had a synergistic effect with 5-HMF in increasing the 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging capacity and ferric ion-reducing antioxidant power (p < 0.05). AA had superior α-glucosidase inhibitory ability increasing from 67.31 to 80.48%. It also reduced the development time by 33%. Therefore, aging technology can enhance the bioactive compounds in oranges and provide a reference for future whole-fruit aging fermentation and health product creation.

The Effect of Yogurt and Kefir Starter Cultures on Bioactivity of Fermented Industrial By-Product from Cannabis sativa Production—Hemp Press Cake

Cannabis sativa (hemp) is a plant considered to be abundant in bioactive compounds. The increasing production of hemp oil is leaving considerable amounts of hemp press cakes (HPC), which have not been sufficiently managed so far. One of the directions of development of plant-based food is the use of by-products of the agri-food industry in accordance with the idea of zero waste and the circular economy, so the purpose of this study was to determine the possibility of HPC fermentation using yogurt and kefir cultures and to determine the effect of the type of starter on the properties of the products. In the present study, starter cultures of yogurt (YO 122) and kefir (commercial grains) were used for HPC fermentation. Changes in lactic acid bacteria (LAB) and yeast population, pH, acidity, the content of bioactive compounds by spectrophotometric methods (proteins, amino acids, polyphenols, flavonoids, reducing sugars) and antioxidant activity (DDPH, ABTS, FRAP and reducing power) were determined. The results showed that it was possible to develop high-value beverages based on HPC with high fermentation efficiency: survivability of LAB and yeast (>106 CFU/g) and acidification (pH in a range of 4.82–6.36 and 5.34–6.49 for yogurt and kefir culture, respectively). Moreover, the stability of hemp protein, with its variable free amino acid composition, antioxidant potential and presented changes in polyphenolic content, was observed during storage. The presented results show a new way to manage HPC as an oil industry residue by using it as a raw material for the development of a bioactive food product and illustrate the relationship between applied starter culture, the direction of fermentation and changes in the content of bioactive compounds.

Synergistic Action of Multiple Enzymes Resulting in Efficient Hydrolysis of Banana Bracts and Products with Improved Antioxidant Properties

This study investigated the effect of enzymatic hydrolysis of banana bracts from different varieties (Maçã, Nanica and Prata) using pectinase, protease and cellulase (singly or in combinations) on their antioxidant properties. The results showed that the antioxidant properties and total phenolic compounds (TPC) of extracts increased after the enzymatic treatment with a clear synergistic effect between the different enzymes. The ternary mixture of pectinase, protease and cellulase resulted in increases of 458% and 678% in TPC content for extracts obtained from Maçã and Nanica varieties and up to 65% in antioxidant properties of those produced from Prata variety compared to the non-hydrolyzed samples. In general, the extracts obtained from the Prata variety showed the highest levels of TPC, as well as antioxidant activity, as follows: 14.70 mg GAE g−1 for TPC, 82.57 µmol TE g−1 for ABTS, 22.26 µmol TE g−1 for DPPH and 47.09 µmol TE g−1 for FRAP. Phenolic compounds identified by HPLC in extracts included ρ-coumaric, ferulic, sinapic and vanillic acids and the flavonoid rutin. This study reported for the first time the enzymatic treatment applied to banana bracts as a promising method to release antioxidant compounds, offering a new opportunity to explore these residues as a source of molecules with high added value through an environmentally friendly and safe process.

In vitro cosmeceutical activity of alcoholic extract from chestnut inner shell fermented with Aspergillus sojae

Chestnut inner shell was fermented in solid state with Aspergillus sojae, and then extracted using ethanol (95%) to analyze its cosmeceutical activity and phenolic composition. The fermentation significantly increased the antioxidant activity, and in vitro cosmeceutical activities. The ethanol extract showed the higher activities than ethyl acetate and water extracts. DPPH radical scavenging activity of the alcoholic extract was 80.53%, and tyrosinase and elastase inhibition activities were 101.01%, and 76.73%, respectively, after 10 days of fermentation. Kojic acid, a secondary metabolite of A. sojae was produced by the fermentation as a major bioactive component. Gallic acid, ellagic acid, and coumaric acid appeared the major phenolic acids in the alcoholic extract from fermented chestnut inner shell. The alcoholic extract from chestnut inner shell fermented by A. sojae may be used as an effective and bioactive cosmeceutical.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01044-9.

Biological Approaches for Extraction of Bioactive Compounds From Agro-industrial By-products: A Review

Bioactive compounds can provide health benefits beyond the nutritional value and are originally present or added to food matrices. However, because they are part of the food matrices, most bioactive compounds remain in agroindustrial by-products. Agro-industrial by-products are generated in large quantities throughout the food production chain and can—when not properly treated—affect the environment, the profit, and the proper and nutritional distribution of food to people. Thus, it is important to adopt processes that increase the use of these agroindustrial by-products, including biological approaches, which can enhance the extraction and obtention of bioactive compounds, which enables their application in food and pharmaceutical industries. Biological processes have several advantages compared to nonbiological processes, including the provision of extracts with high quality and bioactivity, as well as extracts that present low toxicity and environmental impact. Among biological approaches, extraction from enzymes and fermentation stand out as tools for obtaining bioactive compounds from various agro-industrial wastes. In this sense, this article provides an overview of the main bioactive components found in agroindustrial by-products and the biological strategies for their extraction. We also provide information to enhance the use of these bioactive compounds, especially for the food and pharmaceutical industries.