Bacterial cellulose nanofiber-based films incorporating gelatin hydrolysate from tilapia skin: production, characterization and cytotoxicity assessment

In this work, films based on bacterial cellulose nanofibers (BCNFs) incorporating gelatin hydrolysate (GH) from tilapia skin were produced. The effect of plasticizer (sorbitol or glycerol) and GH incorporation was evaluated on the physicalchemical and optical properties of films. BCNFs were produced using bacterial cellulose obtained from Hestrin and Schramm (HS) medium (BCNF-HS) or cashew apple juice (BCNF-CM), which was studied as an alternative to HS. Films with sorbitol showed the best properties and were selected for further characterization, using 40% (w/w) of BCNF-HS, 40% (w/w) of GH and 20% (w/w) of sorbitol (BCNF-HS-S-GH films). These films exhibited an antioxidant activity of 7.8 µmols Trolox Eq/g film, a water vapor permeability (WVP) of 1.6 g.mm/kPa.h.m2 and an Youngs modulus of 0.57 GPa. Films produced with BCNFs obtained from cashew apple juice revealed enhanced tensile strength, elongation at break, and thermal stability. Caco-2 cells viability after incubation with BCNF-based films incorporating GH was evaluated and showed non-cytotoxicity, reinforcing the safety of the developed materials and their potential use in food applications.The authors would like to thank: Foundation of Support to the Scientific and Technological Development (FUNCAP, Brazil), Coordination for the Improvement of Higher Education Personnel (CAPES, Brazil), National Counsel of Technological and Scientific Development (CNPq, Brazil), Minho University (Braga, Portugal) and International Iberian Nanotechnology Laboratory (Braga, Portugal). This work was funded by research projects CNPq n 485465/2012-4, CNPq n 310368/2012-0 and CNPq n 476978/2013-0. Funding from Fundac¸a ˜o para a Cie ˆncia e Tecnologia through the project ‘‘Bacterial Cellulose: a platform for the development of bionanoproducts’’, under the bilateral program FCT/CAPES, is acknowledged. The authors acknowledge also the funding from QREN (‘‘Quadro de Referência Estratégica Nacional’’), ADI (‘‘Agência de Inovação’’) through the project Norte-070202-FEDER-038853, and BioTecNorte operation (NORTE01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte. This research was supported by Norte Regional Operational Program 2014–2020 (Norte2020) through the European Regional Development Fund (ERDF) Nanotechnology based functional solutions (NORTE-01-0145FEDER-000019).info:eu-repo/semantics/publishedVersio

Optimizing the development of an antihypertensive whey hydrolysate in semi-pilot scale

Whey proteins and peptides are byproducts of dairy industry recognized for reducing risk factors of numerous diseases, including hypertension Despite the need of better use of this agroindustrial residue and the high prevalence of hypertension worldwide, whey based-products that are able to modulate blood pressure are very scarce in food and nutraceutical markets, emphasizing the need of more research regarding this theme. The development of new products requires several stages in which scaling-up the production is comprised. In this manner, the present study proposed to optimize the process of development of a new antihypertensive whey hydrolysate in semi-pilot scale, assessing the influence of drying technologies and enzyme inactivation conditions on its biofunctionality. A commercial pepsin (1.91% w/w; 0.28μU.mL-1) was used to catalyse the hydrolysis of a 88% whey protein concentrate solution (1.25%; pH2, 1M HCl; 20L). Reactions occurred for 3h at 37°C, then the enzyme was inactivated either by increasing the temperature to 80°C/5min or the pH to 7 (5M NaOH).The drying method (freeze- and spray-drying) was also assessed concerning the vasorelaxant activity, which was evaluated in rat aortic rings. Peptide profiles of the samples inactivated by temperature were more varied than the chemically inactivated ones. In all samples α-Lactalbumin was completely hydrolyzed while β-Lactoglobulin remained partially resistant. Corroborating with the chemical analyses, hydrolysates thermally inactivated showed vascular relaxations of 72.06% ± 11.36 (freeze-dried) and 81.00% ± 14.27 (spray-dried) (p>0.05), while the samples inactivated by pH reached 20.6% ± 5.4 (freeze-dried) and -9.25% ± 10.18 (spray-dried) of vascular relaxation (p>0.05), which may be possibly related to the formation of NaCl. The results showed that it was possible to develop a whey protein hydrolysate in semi-pilot scale with high antihypertensive activity using a more affordable technology to food industrie