Bioactive compounds recovery by freeze concentration process from winemaking by-product.

Grape pomace is the main solid residue of wine industry, containing high amounts of phenolic compounds. Considering its high potential, an extraction procedure was optimized for maximal recovery of anthocyanins from grape pomace (Vitis vinifera L.) using citric acid as a generally recognized as safe (GRAS) acidulant in water. Volume of solvent (3.2-36.8 mL), time (14.4-165.6 min) and pH of solvent (1.12-4.48) were the studied variables. Furthermore, the best condition to obtain extract rich in anthocyanins was submitted to the gravitational block freeze concentration process. The performance of the process was evaluated and cryoconcentrated and ice fractions were analyzed for physicochemical properties, bioactive compounds content, and antioxidant activity. Interaction, linear, and quadratic effects for volume and pH of solvent were significant by analysis of variance (ANOVA). The experimental design allowed the prediction for maximal recovery of anthocyanins (10 mL of solvent at pH 1.8). The bioactive composition of the optimized grape pomace extract was influenced by the cryoconcentration process. After three cycles using gravitational block freeze concentration, the total phenolics and monomeric anthocyanins were approximately 4 and 5 times higher than the initial condition of the extract, respectively. Consequently, an increase in antioxidant activity was observed. The increase in the concentration of bioactive compounds reached a process efficiency of 93% (stage 1) for phenolic compounds and 91% (stage 2) for anthocyanins. Therefore, the final water-based optimized method is safe and has a low cost and the concentrated extract certainly showed higher concentrations of total phenolics and anthocyanins, compared to the initial extract. The proposed clean extraction method and cryoconcentration technique can be considered important strategies for recovering and valuing grape pomace components, improving the approach to the circular economy concept in the wine industry.

Freeze concentration techniques as alternative methods to thermal processing in dairy manufacturing: A review.

Freeze concentration technology is applied to concentrate liquid foods at low temperatures, thus separating pure ice crystals from the final concentrate solution. This method is an interesting alternative to concentrate food with high water levels and significant nutritional value such as dairy products, since several bioactive compounds are reduced when exposed to elevated temperatures. Considered that, this technique may be a great alternative to concentrating and maintaining both nutritional and sensory characteristics of liquid foods. The present review aims to introduce freeze concentration procedures as an eligible choice for conserving dairy products', also addressing its effects on the dairy matrix. PRACTICAL APPLICATION: This study reports the main techniques of freeze concentration applications in dairy products, to be used both on an industrial and laboratory scale, aiming to improve the nutritional quality of the products obtained.

Influence of guabiroba pulp (campomanesia xanthocarpa o. berg) added to fermented milk on probiotic survival under in vitro simulated gastrointestinal conditions.

In fermented milks inoculated with two thermophilic strains (Lactobacillus bulgaricus and Streptococcus thermophilus), guabiroba pulp (Campomanesia xanthocarpa O. Berg) was added in different concentrations: 5% (I5 sample) and 10% (I10 sample), compared to a control sample, with no pulp addition. In these fermented milks, Bifidobacterium BB-12 was added and the samples were submitted to a progressive gastrointestinal simulation in vitro. The cells count was performed, including the survival rates for all the progressive steps of the simulated digestion. Total phenolic content (TPC) and antioxidant activity analysis by FRAP (Ferric Reducing Antioxidant Power) and DPPH (2,2-diphenyl-1-picrylhydrazyl) were performed in all the gastrointestinal steps. Before and during the entire gastrointestinal tract, the Bifidobacterium BB-12 count was 8-9 log CFU g-1, above the recommended for a probiotic product, with a highlight in intestinal colon steps. The I10 sample showed the highest viable cell count, the highest total phenolic content and antioxidant activity throughout the entire gastric steps (p < 0.05). The fermented milk proved to be an effective matrix for the probiotic stability and incorporation of guabiroba components. Bioactive compounds present in the guabiroba pulp may have occasioned a prebiotic and protective effect on Bifidobacterium BB-12 after gastric conditions. The possible bioconversion of these compounds in more active forms can contribute to the absorption in epithelial cells, enhancing fermented milks with guabiroba pulp as important sources of dietary accessible bioactive compounds.