Grape seed pomace as a valuable source of antioxidant fibers.

BACKGROUND: Grape seed pomace is a valuable by-product from winery/oil extraction industries and a potential source of bioactive compounds. Hot water extraction is the most widely used technology for polysaccharide recovery from plant and seed sources. To obtain an antioxidant fiber-rich extract (AFE) from defatted grape seed pomace, seed:water ratio (1:10-1:20) and extraction temperature (70-90 °C) effects on extraction yield, total sugars, total phenolic compounds and condensed tannins were investigated. RESULTS: The best extraction results were achieved at the highest seed:water ratio and temperature. At these conditions, the extraction yield and total sugar content of the freeze-dried AFE were 100.1 g kg-1 and 725.3 g kg-1 , respectively. The AFE presented high total phenolic content (16.2 g GAE kg-1 ), condensed tannins (515.1 mg CAT kg-1 ), soluble (219.1 g kg-1 ) and insoluble fibers (132.4 g kg-1 ), besides protein (171.1 g kg-1 ) and ash (152.6 g kg-1 ). The antioxidant capacity of the AFE was 382.7, 823.7 and 1439.4 µmol Trolox g-1 for DPPH, ABTS and ORAC methods. CONCLUSION: The AFE was shown to be not only an interesting source of fiber with antioxidant capacity, which could become a potential foodstuff, but also an ecofriendly and sustainable alternative to use grape seed pomace. © 2019 Society of Chemical Industry.

Effect of extruded wheat flour and pre-gelatinized cassava starch on process and quality parameters of French-type bread elaborated from frozen dough.

This study aimed to verify the potential of extruded wheat flour (EWF) or pre-gelatinized cassava starch (PGS) to improve the process and the quality of French bread elaborated from frozen dough. Three formulations were prepared: 100% control wheat flour (CWF) and the other two formulations with 5% substitution of wheat flour by EWF or PGS. Frozen doughs were frozen stored for seven days and after this period they were thawed, fermented, baked and evaluated for physical, chemical and technological characteristics. Available glucose levels found for EWF (12g/100g), and PGS (11.7g/100g) in relation to CWF (7.1g/100g) showed higher sugar availability for yeasts at the initial stage of proofing, and may also have had a cryoprotective effect when freezing bread doughs. The frozen doughs with EWF or PGS, when thawed and fermented, presented higher volume increase, but after baking, they presented lower volume when compared to the control bread. The results of this study are promising for the use of extruded wheat flour or pre-gelatinized cassava starch as sugar providers for doughs' post-freezing proofing process, improving frozen dough process of French-type bread.