Integral use of Isabel grapes to elaborate new products with nutritional value and functional potential

Abstract

The benefits of grape consumption are widely recognized and mostly due to phenolic compounds. These beneficial effects will depend on the bioaccessibility of these compounds on grape and its derivatives. This study elaborated two formulations of Isabel grape preparation: PAX (with agave and xylitol) and PS (with sucrose); and two formulations of Isabel grape flour: FAX (from the PAX process residues) and the FS (from the PS process residues). The products were analyzed regarding their nutritional and antioxidant properties; their phenolic compounds’ bioaccessibility was also verified through a simulated digestion model. The preparation and flour exhibited relevant sugars levels (10.83-49.71 g 100 g-1). Those produced with natural sweeteners had a reduction in sugar concentration of 51% and 29% for preparation and flour, respectively, compared to formulations with sucrose, with the high fiber content in the flour is being further highlighted (20.14-21.95 g 100 g-1). The catechin (2.37-28.11 mg 100 g-1) was the most bioaccessible compound (22% to 168%), which together with the caftaric acid (2.31-69.43 mg 100 g-1) and malvidin 3-glucoside (8.65-16.47 mg 100 g-1) represent the compounds observed in greater quantity. The preparations showed higher bioaccessibility regarding grapes and flours for most of the phenolic compounds. Furthermore, the products elaborated presented higher values of anthocyanins and antioxidant activity than the in natura grape, highlighting the beneficial effect of grape processing.

A fibre and phenolic-rich flour from Isabel grape by-products with stimulatory effects on distinct probiotics and beneficial impacts on human colonic microbiota in vitro

“…Lactobacillus and Bifidobacterium are among the most important bacterial groups in studies with ingredients for use as prebiotics (Ashaolu et al 2020), being recognized as markers of prebiotic effects since these genera are part of the human gut microbiota (David et al 2014;Sun et al 2018). IGF positively affected the growth and metabolic activity of probiotics L. acidophilus, L. casei and B. lactis, and these effects could be primarily linked to the IGF composition rich in dietary fibre (~22 g 100 g −1 ) and phenolic compounds (136Á24 mg 100 g −1 ) (Silva et al 2021). Grape fibre and phenolic compounds are associated with stimulatory effects on the growth and metabolism of different probiotics and beneficial effects on the human gut microbiota (Freire et al 2017;Ma and Chen 2020).…”

“…Isabel (Vitis labrusca L.) at the commercial maturation stage (peel with uniform dark purple colouration) were purchased from a local supermarket (João Pessoa, PB, Brazil). The IGF was prepared with the byproducts after processing the grapes to produce a whole and low-calorie Isabel grape preparation (Silva et al 2021). The residual solids (peels and seeds) comprising the Isabel grape by-products were dried in an air circulation oven until reaching constant weight (60 AE 2°C, approximately 18 h), the dried material was crushed with a domestic blender, and sieved (28 mesh) to obtain a flour (moisture: 6 -7%) (Bender et al 2016).…”

“…The nutritional composition of the IGF was determined in our previous study (Silva et al 2021), standing out its contents of soluble (3Á95 AE 0Á30 g 100 g −1 ) and insoluble fibre (18Á01 AE 0Á01 g 100 g −1 ), presence of glucose (13Á91 AE 0Á26 g 100 g −1 ) and fructose (21Á17 AE 0Á37 g 100 g −1 ), and a variety of phenolic compounds: catechin (28Á11 AE 0Á46 mg 100 g −1 ), epigallocatechin gallate (5Á54 AE 0Á09 mg 100 g −1 ), procyanidin B2 (14Á51 AE 0Á24 mg 100 g −1 ), caftaric acid (69Á43 AE 1Á13 mg 100 g −1 ) and malvidin 3-glucoside (10Á68 AE 0Á17 mg 100 g -1 ).…”

“…products with high added value (Silva et al 2021). Considering the growing concern with sustainability and the circular economy model, the opportunities to reuse grape by-products should bring great socioeconomic and environmental benefits (Ferreira and Santos 2022).…”

“…Increasing attention has been directed to the potential synergistic interactions between fibres and phenolic compounds to improve their positive impacts on the intestinal microbiota and related benefits on host health (Mithul Aravind et al 2021). These synergistic interactions could be exploited by developing foods or dietary supplements naturally rich in fibres and phenolic compounds (Albuquerque et al 2020;Andrade et al 2020), such as those derived from Isabel grape by-products (Silva et al 2021(Silva et al , 2022.…”