Development and sensory test of a dairy product with ACE inhibitory and antioxidant peptides produced at a pilot plant scale

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGA scale-up process was carried out to obtain potent bioactive peptides from whey protein through a simple hydrolysis process. The scale-up was satisfactory, with results similar to those obtained at lab scale: a fraction of peptides < 1 kDa with ACE inhibitory activity of 18.44 ± 2.47 μg/mL, a DPPH value of 69.40 ± 0.44%, and an ORAC value of 3.37 ± 0.03 μmol TE/mg protein. The peptide sequences responsible for the ACE inhibitory activity were also similar to those identified at lab scale: PM, LL, LF, HFKG and PT. The hydrolysate was used as a functional ingredient in a low-fat yoghurt. The consumer sensory taste panel found no significant difference (p > 0.05) between the bitterness of the control and the functional yoghurt, and about 50% of consumers would buy it. The hydrolysate maintained its bioactivities for 4 months at −20 ◦C (after thawing and pasteurisation), and for 1 week in yoghurt at 4 ◦C

Performance and intestinal coliform counts in weaned piglets fed a probiotic culture (Lactobacillus casei subsp. casei CECT 4043) or an antibiotic

The production of biomass and antibacterial extracellular products by Lactobacillus casei subsp. casei CECT 4043 was followed in both batch and in realkalized fed-batch cultures. Enhanced concentrations of biomass and antibacterial extracellular products were obtained with the use of the latter fermentation technique in comparison with the batch mode. The culture obtained by fed-batch fermentation was mixed with skim milk and used to prepare a probiotic feed for weaned piglets. To test the effect of the potentially probiotic culture of L. casei on body weight gain, feed intake, feed conversion efficiency, and on fecal coliform counts of piglets, two groups of animals received either feed supplemented with the probiotic preparation or avilamycin for 28 days. The control group was fed nonsupplemented feed. At the end of the administration period (day 28), the groups receiving probiotic and avilamycin exhibited the highest average body weight gain values, although the mean feed intake and feed conversion efficiency values were not different among the groups (P > 0.05). For the entire experimental period (42 days), the control group exhibited the lowest feed intake value, the probiotic group exhibited the highest feed conversion efficiency value, and the antibiotic group exhibited the highest body weight gain (P 0.05). Fecal coliform values decreased (although not significantly) by day 28 in the three groups. However, the mean counts returned to pretreatment levels by day 42 in all groups.Instituto Nacional de Investigación y Tecnología Agraria | Ref. CAL01-045-C2-

Red seaweed proteins: Valuable marine-origin compounds with encouraging applications

Increased incomes, urbanization, and an aging population, are leading to changes in consumption patterns, resulting in a growing demand for proteins. From a sustainability perspective, there is a consensus that animal protein production has a disproportionately impact on the environment, particularly in intensive systems that require significant amounts of feed crops. Macroalgae have emerged as a promising feedstock for transitioning towards a blue bioeconomy. Red seaweed stands out as a particularly attractive action, as it can contain protein concentrations of up to 47 %, the highest among terrestrial plants and other algae divisions. These proteins offer a rich source of essential amino acids, making them excellent candidates for human food formulation. Nevertheless, compared to other major components such as carbohydrates, red macroalgae proteins remain underexploited. This review focuses on the potential of red algae as a protein source within an environmentally friendly biorefinery development strategy, primarily for food and biomedical applications. It also explores the strategies and limitations associated with protein extraction and purification, emphasizing the need for further in vivo and toxicological studies, particularly regarding the digestibility and bioavailability of red algal proteins.Universidade de Vigo/CISU

Modelling the biphasic growth and product formation by Enterococcus faecium CECT 410 in realkalized fed-batch fermentations in whey

The influence of initial pH on growth and nutrient (total sugars, nitrogen, and phosphorous) consumption by Enterococcus faecium CECT 410 was studied during batch cultures in whey. With these data, two realkalized fed-batch fermentations were developed using different feeding substrates. The shift from homolactic to mixed acid fermentation, the biphasic kinetics observed for cell growth and nitrogen consumption and the increase in the concentrations of biomass and products (lactic acid, acetic acid, ethanol, and butane-2,3-diol) were the most noteworthy observations of these cultures. Modelling the fed-batch growth of Ent. faecium with the Logistic and bi-Logistic models was not satisfactory. However, biomass production was best mathematically described with the use of a double Monod model, which was expressed in terms of biomass, product accumulation, and nitrogen utilization. Product formation was successfully modelled with a modified form of the Luedeking and Piret model developed in this study.Instituto Nacional de Investigación y Tecnología Agraria | Ref. CAL01-045-C2-2Ministerio de Educación y Ciencia | Ref. MAT2005-05393-C03-03Ministerio de Educación y Ciencia | Ref. MAT2006-11662- C03-0

Effects of feeding of two potentially probiotic preparations from lactic acid bacteria on the performance and faecal microflora of broiler chickens

The aim of this study was to evaluate the potential of two probiotic preparations, containing live lactic acid bacteria (Lactococcus lactis CECT 539 and Lactobacillus casei CECT 4043) and their products of fermentation (organic acids and bacteriocins), as a replacement for antibiotics in stimulating health and growth of broiler chickens. The effects of the supplementation of both preparations (with proven probiotic effect in weaned piglets) and an antibiotic (avilamycin) on body weight gain (BWG), feed intake (FI), feed consumption efficiency (FCE), relative intestinal weight, and intestinal microbiota counts were studied in 1- day posthatch chickens. The experiments were conducted with medium-growth Sasso X44 chickens housed in cages and with nutritional stressed Ross 308 broiler distributed in pens. Consumption of the different diets did not affect significantly the final coliform counts in Sasso X44 chickens. However, counts of lactic acid bacteria and mesophilic microorganisms were higher in the animals receiving the two probiotic preparations (P < 0.05). In the second experiment, although no differences in BWG were observed between treatments, Ross 308 broilers receiving the probiotic Lactobacillus preparation exhibited the lowest FCE values and were considered the most efficient at converting feed into live weight.Instituto Nacional de Investigación y Tecnología Agraria | Ref. CAL01-045-C2-

Microfluidics potential for developing food-grade microstructures through emulsification processes and their application

The food sector continues to face challenges in developing techniques to increase the bioavailability of bioactive chemicals. Utilising microstructures capable of encapsulating diverse compounds has been proposed as a technological solution for their transport both in food and into the gastrointestinal tract. The present review discusses the primary elements that influence the emulsification process in microfluidic systems to form different microstructures for food applications. In microfluidic systems, reactions occur within small reaction channels (1–1000 μm), using small amounts of samples and reactants, ca. 102–103 times less than conventional assays. This geometry provides several advantages for emulsion and encapsulating structure production, like less waste generation, lower cost and gentle assays. Also, from a food application perspective, it allows the decrease in particle dispersion, resulting in a highly repeatable and efficient synthesis method that also improves the palatability of the food products into which the encapsulates are incorporated. However, it also entails some particular requirements. It is important to obtain a low Reynolds number (Re < approx. 250) for greater precision in droplet formation. Also, microfluidics requires fluid viscosity typically between 0.3 and 1400 mPa s at 20 °C. So, it is a challenge to find food-grade fluids that can operate at the micro-scale of these systems. Microfluidic systems can be used to synthesise different food-grade microstructures: microemulsions, solid lipid microparticles, microgels, or self-assembled structures like liposomes, niosomes, or polymersomes. Besides, microfluidics is particularly useful for accurately encapsulating bacterial cells to control their delivery and release on the action site. However, despite the significant advancement in these systems' development over the past several years, developing and implementing these systems on an industrial scale remains challenging for the food industry.Universidade de VigoConsejo Nacional de Investigaciones Científicas y Técnicas (Argentina)Universidade de Vigo/CISU

Biofunctionality assessment of α-lactalbumin nanotubes

The functional properties α-LA nanotubes and the gels formed during their synthesis were studied to evaluate their potential applications. The bioactivity of α-LA was improved by the synthesis of nanotubes, with significantly (p < 0.05) higher ACE-inhibitory (IACE) and antioxidant activity (μmol TE/mg protein). The IC50 (protein concentration to inhibit 50% of ACE activity) of α-LA nanotubes was 281 ± 21 μg mL−1 and the antioxidant activity 1.28 ± 0.01 μmol TE mg−1 protein. Besides, the IACE-value was significantly higher (p < 0.05) when the α-LA fragments incorporated into the nanotube’ structure were considered, and not only the low MW peptides formed during the nanotube synthesis (not incorporated into the nanotube’ structure).This study also analysed how different ion ratios in the synthesis of α-LA nanotubes changed their functionality. Thus, gels formed by long and regular α-LA nanotubes (2 mol of Mn2+/mol of α-LA) showed fluid−gel characteristics, with some time-dependent shear-thinning flow (thixotropy). At fixed recovery time, a less thixotropic behaviour was found in these fluid gels (high percentage −71.6 ± 7.4%− of structural regeneration). Additionally, they stayed in gel form at high temperatures and even increased their stiffness up to 65 °C. The increase in the ion ratio (3 mol of Mn2+/mol of α-LA) during nanotube synthesis modified the α-LA nanotubes' microstructure nanotubes resulting in short and branched nanotubes. These gels showed a higher level of pseudo-plasticity, higher consistency and thixotropy. These are characteristics of a more complex and dense network with greater time dependence and lower structural regeneration (18.6 ± 2.0%)Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGXunta de Galicia | Ref. ED431E 2018/0

Evaluation of two bacteriocin-producing probiotic lactic acid bacteria as inoculants for controlling Listeria monocytogenes in grass and maize silages

This study evaluated the effectiveness as silage inoculants of two bacteriocin-producing lactic acid bacteria (LAB) with proven probiotic activity in post-weaned piglets, Lactococcus lactis CECT 539 and Pediococcus acidilactici NRRL B-5627, in combination with the ensiling strain Lactobacillus plantarum CECT 220. Four combinations of LAB were tested in grass and maize silages: L. plantarum (Lb), L. plantarum + L. lactis (LbL), L. plantarum + P. acidilactici (LbP), and the three species together (LbLP). Untreated silages and silages inoculated with commercial starters (L. plantarum + Lactobacillus buchneri + Enterococcus faecium) were prepared and used as controls. Since both bacteriocinogenic strains have shown antilisterial activity in vitro, this study also aimed to determinate their effectiveness for controlling Listeria monocytogenes in the silo. Therefore, silages were inoculated with the strain L. monocytogenes CECT 4032 (1.0 × 105 cfu/g), the evolution of which was monitored throughout fermentation using microbiological and DNA based methods. Each treatment was assayed in triplicate in lab-scale silos and sampled after 1, 2, 8, 16 and 30 days to extract DNA and determination of the pH, volume, organic acids (lactic, acetic, propionic and butyric), alcohols (ethanol and propane-1, 2-diol), water soluble reducing sugars (WSRS) and make LAB and L. monocytogenes counts. Our results showed that the silages treated with bacteriocin-producing LAB had a higher rate of pH decline (P < 0.01) and lactic acid production (P < 0.01). After 30 days of fermentation, we observed low acetic acid (P < 0.01) and ethanol (P < 0.01), lower LAB counts (P < 0.01) and higher (P < 0.01) residual sugar concentrations in the Lb, LbL, LbP and LbLP silages. No L. monocytogenes colonies were found during ensilage; however, its DNA was present, which suggests that the adverse silage conditions (pH, anaerobiosis) might favour a viable but non-culturable state in the cells. In both forages, all treatments showed the anticipated disappearance of L. monocytogenes, unlike the control. It can be concluded that the bacteriocinogenic LAB tested in this study can be used as silage inoculants for controlling L. monocytogenes in the silo and also in the rumen of cattle due to their reported tolerance to acid.Xunta de Galicia | Ref. 03MFU0

Use of poly(N‐isopropylacrylamide) nanohydrogels for the controlled release of pimaricin in active packaging

We propose here a delivery drug‐polymer system using poly(N‐isopropylacrylamide) (PNIPA) nanohydrogels that enables pimaricin to be protected from hostile environments and allows the controlled release of the antifungal through environmental stimuli. We synthesized 2 nanohydrogels, 1 with 100% N‐isopropylacrylamide (PNIPA(5)) and 1 with 80% N‐isopropylacrylamide copolymerized and 20% acrylic acid (PNIPA‐20AA(5)). Both were then, loaded with a pimaricin aqueous solution. The pimaricin release profiles of these 2 nanohydrogels were considerably different: PNIPA(5) released 10% and PNIPA‐20AA(5) released 30% with respect to the free pimaricin release. Moreover, the diffusion experiments showed that pimaricin was released from the PNIPA‐20AA(5) nanohydrogel for up to 3 times longer than free pimaricin. Therefore, incorporating acrylic acid as comonomer into the PNIPA nanohydrogel resulted in a slower but more continuous release of pimaricin. The highest pimaricin levels were reached when the most hydrophilic nanohydrogel was used. The bioassay results showed that the pimaricin‐nanohydrogel system was highly effective in inhibiting the growth of the indicator strain in conditions of thermal abuse. The spoilage in acidified samples stored under fluorescent lighting was reduced by 80.94%± 33.02% in samples treated with a pimaricin‐loaded nanohydrogel, but only by 19.91%± 6.68% in samples treated with free pimaricin. Therefore, 2 conclusions emerge from this study. One is that the nanohydrogel delivery system could impede the degradation of pimaricin. The other is that the inhibitory effect of the antifungal on yeast growth is more pronounced when it is added included into the nanohydrogel to the food, especially in an acidic environment. Practical Application:  This article presents relevant results on the use of nanohydrogels in food packaging. Nanohydrogels could provide protection so that the pimaricin remains active for a longer time. They also allow the controlled release of pimaricin, which thus regulates the unnecessary presence of the antifungal in the food.Ministerio de Educación y Ciencia | Ref. MAT2006-11662-C03-01Ministerio de Educación y Ciencia | Ref. MAT2006-11662-C03-02Ministerio de Educación y Ciencia | Ref. MAT2006-11662-C03-03Ministerio de Ciencia e Innovación | Ref. MAT2010-21509-C03-01Ministerio de Ciencia e Innovación | Ref. /EUI 2008-00115Universidade de Vig

Evaluation of a chitosan-based edible film as carrier of natamycin to improve the storability of Saloio cheese

The purpose of this study was to evaluate the effects of the application of chitosan coating containing natamycin on the physicochemical and microbial properties of semi-hard cheese. Three cheese groups were prepared: samples without coating, samples coated with chitosan and with chitosan containing 0.50 mg mL1 of natamycin, whose minimum inhibitory concentration was previously determinated on cheese surface. Microbiological analyses showed that natamycin coated samples presented a decrease on moulds/yeasts of 1.1 log (CFU g1) compared to control after 27 days of storage. Addition of natamycin also affected O2 and CO2 permeability, increasing from 7.12 to 7.68 × 1015 g·(Pa s m)1, and from 10.69 to 64.58 × 1014 g·(Pa s m)1, respectively. The diffusion coefficient values of natamycin from the film to phosphate buffered saline solution and to the cheese were 3.60 × 1010 and 1.29 × 1012 cm2 s1, respectively. This study demonstrated that chitosan-based coating/films can be used as release system containing natamycin to create an additional hurdle for moulds/yeasts in cheese thus contributing to extend its shelf-life.Fundação para a Ciência e a Tecnologia | Ref. SFRH/BD/32566/200