Ethanol Precipitation of Mannooligosaccharides from Subcritical Water-Treated Coconut Meal Hydrolysate

Functional β-mannooligosaccharides: Sources, enzymatic production and application as prebiotics

One of the emerging non-digestible oligosaccharide prebiotics is β-mannooligosaccharides (β-MOS). β-MOS are β-mannan derived oligosaccharides, they are selectively fermented by gut microbiota, promoting the growth of beneficial microorganisms (probiotics), whereas the growth of enteric pathogens remains unaffected or gets inhibited in their presence, along with production of metabolites such as short-chain fatty acids. β-MOS also exhibit several other bioactive properties and health-promoting effects. Production of β-MOS using the enzymes such as β-mannanases is the most effective and eco-friendly approach. For the application of β-MOS on a large scale, their production needs to be standardized using low-cost substrates, efficient enzymes and optimization of the production conditions. Moreover, for their application, detailed in-vivo and clinical studies are required. For this, a thorough information of various studies in this regard is needed. The current review provides a comprehensive account of the enzymatic production of β-MOS along with an evaluation of their prebiotic and other bioactive properties. Their characterization, structural-functional relationship and in-vivo studies have also been summarized. Research gaps and future prospects have also been discussed, which will help in conducting further research for the commercialization of β-MOS as prebiotics, functional food ingredients and therapeutic agents.

A Comparative Assessment on the Recovery of Pectin and Phenolic Fractions from Aqueous and DES Extracts Obtained from Melon Peels

This work evaluates the purification of melon peel extracts obtained by two eco-friendly methods: autohydrolysis and sodium acetate/urea/water extraction (1:3:1.6), an alkaline deep eutectic solvent (DES). For that, sequential ethanol precipitation and resin adsorption/desorption stages were proposed for the separate recovery of the pectic and phenolic fractions. In order to screen the optimal purification conditions, in a first step, the effect of ethanol concentrations (from 70 to 85%) on the precipitation of pectic oligosaccharides was assayed. Subsequently, the influence of the selected resin (Amberlite XAD4, XAD16HP and XAD7HP), liquid/resin ratios, and desorption sequences (varying ethanol concentrations and pH) on the phenolic compounds was also studied. The highest pectin yields were achieved with 85% ethanol: 16.11 and 18.05 g pectin/100 g water-insoluble solids (WIS) for autohydrolysis and DES extracts, respectively. All pectins presented a galacturonic acid content of about 45%, while autohydrolysis pectin presented a higher amount of neutral sugar side chains. The presence of low methoxyl GalA and both linear and branched OGalA with DP from 2 to 20 was also confirmed by FTIR and HPAEC-PAD analysis, respectively. Concerning the phenolic fraction, the resin adsorption and desorption steps at the selected conditions (XAD4 resin, liquid/resin ratio of 2 mL/g, eluted with 50% ethanol thrice) resulted in 79.55 and 4.08 mg GAE/g non-volatile content (NVC) for autohydrolysis and DES extracts, respectively, with improved antioxidant capacity. Moreover, some phenolic acids (protocatechuic and ferulic acids) and flavonoids (orientin, vitexin and naringenin) were quantified in the extracts by HPLC–PDA-MS/MS.

Preliminary Characterisation of Wastes Generated from the Rapeseed and Sunflower Protein Isolation Process and Their Valorisation in Delaying Oil Oxidation

Since rapeseed and sunflower meals are two of the most representative oilseed crops in the world, this study was focused on ethanol-wash solutes (EWS) obtained as wastes from the protein isolation process of rapeseed and sunflower meals. These meals have been previously valorised; however, the use of the EWS is unexplored. The present study is aimed at the characterisation of their phenolic profile, and antioxidant capacity for preventing lipid oxidation in rapeseed, sunflower, and soybean oil, which has been used as a reference oil. The sunflower EWS exhibited more total phenolic compounds (TPC) and antioxidant activity (119.39 ± 1.13 mg GA/g and 193.97 ± 9.77 mg TE/g, respectively) than the rapeseed one (103.44 ± 5.94 mg GA/g and 89.51 ± 3.17 mg TE/g). The phenolic identification showed hydroxybenzoic and protocatechuic acid in the rapeseed EWS, and pyrogallol and caffeic acid in the sunflower EWS, as the main representative phenols. Both EWS at 15% increased significantly (p < 0.05) the oxidative stability of the oils in the Rancimat equipment with values of antioxidant activity index (AAI) from 1.01 to 1.20, depending on the type of oil employed. In conclusion, the rapeseed and sunflower EWS showed great potential, and they could be used as a source of natural antioxidants within the food industry, replacing the synthetic ones, and promoting the circular economy since they are agro-food wastes.