Application of emerging technologies to obtain legume protein isolates with improved techno-functional properties and health effects.

Current demand of consumers for healthy and sustainable food products has led the industry to search for different sources of plant protein isolates and concentrates. Legumes represent an excellent nonanimal protein source with high-protein content. Legume species are distributed in a wide range of ecological conditions, including regions with drought conditions, making them a sustainable crop in a context of global warming. However, their use as human food is limited by the presence of antinutritional factors, such as protease inhibitors, lectins, phytates, and alkaloids, which have adverse nutritional effects. Antitechnological factors, such as fiber, tannins, and lipids, can affect the purity and protein extraction yield. Although most are removed or reduced during alkaline solubilization and isoelectric precipitation processes, some remain in the resulting protein isolates. Selection of appropriate legume genotypes and different emerging and sustainable facilitating technologies, such as high-power ultrasound, pulsed electric fields, high hydrostatic pressure, microwave, and supercritical fluids, can be applied to increase the removal of unwanted compounds. Some technologies can be used to increase protein yield. The technologies can also modify protein structure to improve digestibility, reduce allergenicity, and tune technological properties. This review summarizes recent findings regarding the use of emerging technologies to obtain high-purity protein isolates and the effects on techno-functional properties and health.

Quality changes and shelf-life extension of ready-to-eat fish patties by adding encapsulated citric acid.

BACKGROUND: Citric acid is commonly used as a flavoring and preservative in food and beverages. The effect of adding citric acid directly or encapsulated (each at 1 and 2 g kg-1 ) on the quality and shelf-life of ready-to-eat sea bass patties was evaluated during storage at 4 °C in vacuum skin packaging. RESULTS: Microbial growth and total basic volatile nitrogen were maintained at relatively low levels up to 8 weeks of storage. With respect to oxidative stability, the addition of encapsulated citric acid minimized secondary oxidation values more efficiently than its direct addition, regardless of the concentration. This is in agreement with the decreased fishy odor observed in those patties containing encapsulated citric acid. Accordingly, sensory analysis showed that the addition of encapsulated citric acid at 1 g kg-1 resulted in lower scores in fish aroma compared to that of the control. Sourness is dependent on the amount of citric acid added, regardless of the form (direct or encapsulated). CONCLUSIONS: The form of citric acid addition, rather than the amount of citric acid added, caused changes in texture. Therefore, the use of encapsulated citric acid represents a suitable strategy that is of great interest in the seafood industry. © 2017 Society of Chemical Industry.

Bioaccessibility of hydroxytyrosol and n-3 fatty acids as affected by the delivery system: simple, double and gelled double emulsions.

This study examines the influence of different food-grade n-3 PUFA-enriched simple emulsion (SE), double emulsion (DE) and gelled double emulsion (GDE) delivery systems on the extent of lipolysis, antioxidant capacity and the bioaccessibility of hydroxytyrosol (HTy). GDE emulsion offered better protection for HTy (89%) than the other systems (79% in SE and DE). The reducing capacity of the emulsions containing HTy were not altered during oral digestion. However, "in vitro" gastric and intestinal phases significantly reduced the antioxidant activity of all systems. The structural and physical state of GDE entailed a slowing-down of triacylglyceride hydrolysis (36.4%) in comparison with that of SE and DE (22.7 and 24.8% for SE and DE, respectively).

Salmosan, a ß-Galactomannan-Rich Product, Protects Epithelial Barrier Function in Caco-2 Cells Infected by Salmonella enterica Serovar Enteritidis.

BACKGROUND: One promising strategy for reducing human salmonellosis induced by Salmonella Enteritidis is to supplement animal diets with natural feed additives such as mannan oligosaccharides (MOSs). OBJECTIVE: We sought to investigate the potential role of Salmosan (S-ßGM), an MOS product extremely rich in ß-galactomannan, in preventing epithelial barrier function disruption induced by S. Enteritidis colonization in an in vitro model of intestinal Caco-2 cells in culture. METHODS: Differentiated Caco-2 cells were incubated for 3 h with S. Enteritidis at a multiplicity of infection of 10 in the absence or presence of 500 µg S-ßGM/mL. Paracellular permeability (PP) was assessed by transepithelial electrical resistance (TER), d-mannitol, and fluorescein isothiocyanate-dextran (FD-4) flux. Tight junction proteins and cytoskeletal actin were also localized by confocal microscopy. Reactive oxygen species (ROS) and lipid peroxidation products were evaluated. Scanning and transmission electron microscopy were used to visualize S. Enteritidis adhesion to, and invasion of, the Caco-2 cell cultures. RESULTS: Compared with controls, TER was significantly reduced by 30%, and d-mannitol and FD-4 flux were significantly increased by 374% and 54% in S. Enteritidis-infected cultures, respectively. The presence of S-ßGM in infected cultures induced total recoveries of TER and FD-4 flux to values that did not differ from the control and a partial recovery of d-mannitol flux. These effects were confirmed by immunolocalization of actin, zonula occludens protein 1, and occludin. Similar results were obtained for Salmonella Dublin. The protection of S-ßGM on PP in infected cultures may be associated with a total recovery of ROS production to values that did not differ from the control. Moreover, S-ßGM has the capacity to agglutinate bacteria, leading to a significant reduction of 32% in intracellular S Enteritidis. CONCLUSION: The results demonstrate that S-ßGM contributes to protecting epithelial barrier function in a Caco-2 cell model disrupted by S. Enteritidis.

Double emulsions to improve frankfurter lipid content: impact of perilla oil and pork backfat.

BACKGROUND: The technology involving the use of water-in-oil-in-water double emulsions (DEs) offers an interesting approach to improve the fat content of foods. With this aim, the effect on frankfurter properties of replacing pork backfat with two different DEs prepared using perilla oil and pork backfat as lipid phases was assessed. This strategy was compared with straightforward addition of the lipid source and addition by means of an oil-in-water (O/W) emulsion. RESULTS: As compared with all-pork-fat frankfurters, the ones with perilla oil had a higher proportion of n-3 polyunsaturated fatty acids. Reduced-fat frankfurters had similar water- and fat-binding properties irrespective of the lipid source or the technological strategy used to incorporate it. Moreover, the oil source but not its mode of incorporation determined the oxidation levels of frankfurters. In reduced-fat samples, except in the case of frankfurters formulated with a perilla oil-in-water emulsion, hardness was unaffected either by the type of fat or by its mode of incorporation. The replacement of pork backfat by perilla oil reduced the overall acceptability of products when perilla oil was added by means of the O/W emulsion and DE approaches. CONCLUSION: This technology is suitable for labelling meat products with specific nutritional and health claims.

Zinc Protoporphyrin-Rich Pork Liver Homogenates as Coloring Ingredients in Nitrite-Free Liver Pâtés.

This study aimed to investigate the coloring ingredient potential of liver homogenates that form Zn protoporphyrin (ZnPP), a natural red pigment, after anaerobic incubation. Liver homogenates were used to develop nitrite-free sterile pork liver pâtés. These homogenates were applied in the formulation of pâtés directly or after centrifugation to obtain a pellet that was highly concentrated in ZnPP. Both the whole homogenate and its insoluble fraction were adjusted to pH 7.5 before their use in the formulation of pâtés with and without antioxidant (0.5% ascorbate plus 0.1% tocopherol) addition. Pâtés formulated with the whole homogenate showed color and texture characteristics that were similar to those of the positive control with nitrite. However, high levels of the insoluble fraction also led to pâtés with improved color characteristics but with a two-fold softened texture. Therefore, the form and amount of ZnPP added played roles in the final appearance of the product. The ZnPP pigment was more stable than heme in the sterilization treatment, and antioxidant addition proved to be unnecessary. The ZnPP-rich ingredients allowed for the preparation of nitrite-free cooked liver pâtés with a stable red color and could thus be potentially applied in other uncured cooked meat products.

Nitrosyl-heme and Heme Iron Intake from Processed Meats and Risk of Colorectal Cancer in the EPIC-Spain Cohort.

BACKGROUND: The International Agency for Research on Cancer classified processed meats (PM) as "carcinogenic" and red meat as "probably carcinogenic" for humans. The possible relationship between colorectal cancer risk and the mechanisms involved in the carcinogenesis of PMs have not been established yet. Nitrosyl-heme and heme iron have been proposed as potential-related compounds. The aim of this study was to determine the association between nitrosyl-heme and heme iron intake and colorectal cancer risk among participants from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Spain study. METHODS: This prospective study included 38,262 men and women from the EPIC-Spain study. Food consumption was assessed using diet history and food composition tables. Heme iron and nitrosyl-heme intake were determined by estimating the intake of PM items and conducting laboratory analyses. HR estimates were obtained by proportional hazard models, stratified by age at recruitment and study center and adjusted for sex, total energy intake, education, smoking, body mass index, waist size, physical activity, lifetime alcohol, fibre, calcium, and familiar colorectal cancer history. RESULTS: During a mean follow-up of 16.7 years, 577 participants were diagnosed with colorectal cancer. We found no overall association between nitrosyl-heme [HRT3vsT1, 0.98; 95% confidence interval (CI), 0.79-1.21] or heme iron intakes (HRT3vsT1, 0.88; 95% CI, 0.70-1.10) with colorectal cancer risk, nor according to tumor subtypes. CONCLUSIONS: Our study found no evidence supporting a link between nitrosyl-heme or heme iron intake and colorectal cancer risk in Spanish subjects. IMPACT: As research on nitrosyl-heme is preliminary, more heterogeneous studies are necessary to provide more convincing evidence on their role in colorectal cancer carcinogenesis.

Nitrosyl-Heme and Heme Iron Intake from Processed Meats in Subjects from the EPIC-Spain Cohort.

BACKGROUND: The consumption of processed meats (PMs) and red meats are linked to the likelihood of developing colorectal cancer. Various theories have been proposed to explain this connection, focusing on nitrosyl-heme and heme iron intake. We hypothesized that differences in nitrosyl-heme and heme iron intakes will be associated with various sociodemographic and lifestyle factors. METHODS: The study included 38,471 healthy volunteers (62% females) from five Spanish regions within the EPIC-Spain cohort. High-Performance Liquid Chromatography (HPLC) determined nitrosyl-heme and heme iron levels in the 39 most consumed PMs. Food intake was assessed using validated questionnaires in interviews. Nitrosyl-heme and heme iron intakes, adjusted for sex, age, body mass index (BMI), center, and energy intake, were expressed as geometric means due to their skewed distribution. Variance analysis identified foods explaining the variability of nitrosyl-heme and heme iron intakes. RESULTS: The estimated intakes were 528.6 µg/day for nitrosyl-heme and 1676.2 µg/day for heme iron. Significant differences in nitrosyl-heme intake were found by sex, center, energy, and education level. Heme iron intake varied significantly by sex, center, energy, and smoking status. "Jamón serrano" and "jamón cocido/jamón de York" had the highest intake values, while "morcilla asturiana" and "sangrecilla" were key sources of nitrosyl-heme and heme iron. CONCLUSIONS: This is the first study to estimate levels of nitrosyl-heme intake directly in PMs for a large sample, revealing variations based on sex, BMI, smoking, and activity. Its data aids future exposure estimations in diverse populations.

Determination of total plasma hydroperoxides using a diphenyl-1-pyrenylphosphine fluorescent probe.

Plasma hydroperoxides (HPs) are widely accepted to be good indicators of oxidative stress. By means of the method proposed here, which uses diphenyl-1-pyrenylphosphine (DPPP) as a fluorescent probe, all types of plasma HP were determined. The limits of detection and quantification of the method were 0.08 and 0.25 nmol of cumene hydroperoxide (CHP) equivalents in 40 µl of plasma, respectively. The method is satisfactory in terms of precision (5.3% for 14.5 µM CHP eq., n=8), and the recoveries were 91% and 92% after standard additions of 26 and 52 µM CHP, respectively. The selectivity of the proposed method is higher than 96%. Moreover, optimization of the reaction conditions and the addition of ethylenediaminetetraacetic acid (EDTA) disodium salt and 2,6-di-tert-butyl-4-methylphenol (BHT) prevented the formation of HP artifacts during the analysis. Therefore, the proposed method is useful for simple and quantitative determination of total plasma HPs.

Separation of α-Lactalbumin-Enriched Fractions from Caprine and Ovine Native Whey Concentrate by Combining Membrane and High-Pressure Processing.

Whey from goat and sheep have been gaining attention in the last few years for their nutritional properties. Unfortunately, ß-Lg, not found in human milk, may trigger infant allergies if used in infant food formulations, so there is a growing interest in developing ingredients derived from whey with higher α-La/ß-Lg ratios. The objective of this work was to study the effect of high-pressure processing (HPP) on caprine and ovine native whey concentrates (NWC) in order to obtain α-Lactalbumin (α-La)-enriched fractions. NWCs were treated at 600 MPa (23 °C) for 2, 4, and 15 min and two pH conditions were studied (physiological pH and pH 4.60). The concentration of ß-Lg in supernatant fraction after HPP significantly decreased after 2 min of treatment, while the concentration of α-La was unchanged in both goat and sheep samples. Longer HPP processing times (up to 15 min) progressively increased α-La purification degree but also decreased the α-La yield. Caprine and ovine NWCs treated at physiological pH provided better α-La yield, α-La purification degree, and higher ß-Lg precipitation degrees than the corresponding acidified samples, while the corresponding NWC supernatant (NWCsup) showed lower values for both surface hydrophobicity and total free thiol indices, suggesting a higher extent of protein aggregation. Effects of sample acidification and the HPP treatment were opposite to those previously reported on bovine NWC, so further characterization of caprine and ovine ß-Lg should be carried out to understand their different behavior.

Role of Enzymatic Reactions in Meat Processing and Use of Emerging Technologies for Process Intensification.

Meat processing involves different transformations in the animal muscle after slaughtering, which results in changes in tenderness, aroma and colour, determining the quality of the final meat product. Enzymatic glycolysis, proteolysis and lipolysis play a key role in the conversion of muscle into meat. The accurate control of enzymatic reactions in meat muscle is complicated due to the numerous influential factors, as well as its low reaction rate. Moreover, exogenous enzymes are also used in the meat industry to produce restructured products (transglutaminase), to obtain bioactive peptides (peptides with antioxidant, antihypertensive and gastrointestinal activity) and to promote meat tenderization (papain, bromelain, ficin, zingibain, cucumisin and actinidin). Emerging technologies, such as ultrasound (US), pulsed electric fields (PEF), moderate electric fields (MEF), high-pressure processing (HPP) or supercritical CO2 (SC-CO2), have been used to intensify enzymatic reactions in different food applications. This review aims to provide an overview of the enzymatic reactions taking place during the processing of meat products, how they could be intensified by using emerging technologies and envisage potential applications.

Utilization of Porcine Livers through the Formation of Zn-Protoporphyrin Pigment Optimized by a Response Surface Methodology.

There is a growing demand for clean-label products. This study aimed to obtain a food-grade coloring ingredient for meat products based on the formation of Zn-protoporphyrin from porcine livers, thus contributing to the development of nitrite-free products. First, the effects of sodium disulfite and acetic, ascorbic, and lactic acids on the formation of Zn-protoporphyrin and the total microbial count were studied. The combination of ascorbic and acetic acids resulted in a higher Zn-protoporphyrin content than acetic acid alone, and microbial levels were maintained (ca. 3 log CFU/mL). Second, a response surface methodology was used to maximize Zn-protoporphyrin while maintaining microbiological food standards. To that end, the effects of pH (4.2-5.4), incubation time (3-30 h), and temperature (25-50 °C) were studied. The selected conditions for Zn-protoporphyrin formation involved anaerobic incubation at pH 4.8 and 45 °C for 24 h. The safety was validated through challenge testing for relevant pathogens (Listeria monocytogenes, Salmonella spp., and Clostridium perfringens). A significant reduction (>6 log units) was observed in the selected conditions for L. monocytogenes and Salmonella, whereas C. perfringens spores remained at the inoculated levels. The optimized procedure is proven to be microbiologically safe, and may improve the color of nitrite-free meat products.

Valorisation of pork by-products to obtain antioxidant and antihypertensive peptides.

The porcine liver could be used for the extraction of zinc-protoporphyrin (ZnPP) as a natural red meat pigment. During the autolysis process, porcine liver homogenates was incubated at pH 4.8 and 45 °C under anaerobic conditions to obtain insoluble ZnPP. After incubation, the homogenates were readjusted at pH 4.8, and at pH 7.5 before being centrifuged at 5500 × g for 20 min at 4 °C and the resulting supernatant were compared with the obtained at pH 4.8 at the beginning of the incubation. The molecular weight distributions of the porcine liver fractions at both pHs were very similar, however, eight essential amino acids were more abundant in fractions obtained at pH 4.8. Regarding the ORAC assay, porcine liver protein fraction at pH 4.8 showed the highest antioxidant capacity but antihypertensive inhibition was similar for both pHs. Peptides with strong bioactivity potential from aldehyde dehydrogenase, lactoylglutathione lyase, SEC14-like protein 3 and others were identified. The findings have demonstrated the potential of the porcine liver to extract natural pigments and bioactive peptides.

Formation of Zn-protoporphyrin during the elaboration process of non-nitrified serrano dry-cured hams and its relationship with lipolysis.

This study assessed the ZnPP content, heme content, salt content, and instrumental color in the biceps femoris and semimembranosus muscles during the elaboration of Serrano dry-cured ham manufactured without the addition of nitrate and nitrite for 15 months. The effects of lipolysis and lipid oxidation on the content of Zn-protoporphyrin were also investigated in the biceps femoris. We found that the maximum formation of Zn-protoporphyrin occurred between end of resting and 6 months of processing, which coincides with temperature increase during processing and the end of salt equalization. Zn-protoporphyrin further increased in the biceps femoris until 9 months of processing but remained unchanged in the semimembranosus. Free fatty acid content increased till 6 months and then remained unchanged until the end of the process. These findings and those from an in vitro study reinforced the idea that the release of free fatty acids can promote the activity of the endogenous enzyme ferrochelatase and contribute to the formation of Zn-protoporphyrin from heme. However, the content of Zn-protoporphyrin decreased at the end of the processing, which may be due to the progression of lipid oxidation.

Consumer Attitudes toward Consumption of Meat Products Containing Offal and Offal Extracts.

The development of food products containing offal and offal extracts could be part of the solution to the upcoming demand for animal protein. This study aimed to determine Spanish consumers' attitudes toward offal and the development of meat products containing offal extracts. Consumers' perceptions were evaluated by means of focus group discussions and a survey (N = 400) to validate the focus group results in various Spanish provinces. The theory of planned behavior was used to examine consumer attitudes. Results indicated that nutritional properties, environmental sustainability, and affordability were the main drivers, while sensory attributes, low frequency consumption, and perceived higher content of undesirable compounds were the main barriers. Three segments were identified according to their beliefs: those in favor of these products, those that were health and environmentally conscious, and those who were reluctant about them. The identification of these segments and their profiles demonstrated the necessity to focus efforts on providing reliable information on sensory and health-related issues to improve acceptability. Attitude was the most important predictor of behavioral intention regarding the global model, while the social component (subjective norm) was significant for two of the identified segments, emphasizing the relevance of the social component for acceptability.

Effects of post mortem pH and salting time on Zinc-protoporphyrin content in nitrite-free Serrano dry-cured hams.

There is a growing demand for clean label products and thus the elimination of curing additives in various dry-cured meats is of interest while maintaining colour characteristics. This study was aimed to examine the effect of pH at 24 h post mortem (pHSM24h ≤ 5.4; 5.4 > pHSM24h < 5.9; pHSM24h ≥ 5.9) and salting time (standard vs reduced) on zinc-protoporphyrin content, heme content and other physicochemical parameters of Serrano dry-cured hams manufactured without the addition of curing agents. Results showed that in those hams with higher post mortem pH heme content was increased whereas ZnPP content and proteolysis index were decreased. Reduced salting time decreased salt content whereas ZnPP and heme contents remained unaffected. Lower post mortem pH and reduced salting time led to a higher content in various free fatty acids which, in turn, were found to correlate positively with ZnPP formation. However, the observed changes in heme and ZnPP contents had no effect on the instrumental color of the final product.

Fatty acid composition and parasitism of European sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) populations in the northern Catalan Sea in the context of changing environmental conditions.

The status of sardine and anchovy populations in the northern Mediterranean Sea has been declining in recent decades. In this study, fatty acids and parasitism at different reproductive and feeding stages in these two species were assessed using specimens caught along the northern Catalan coast, in order to assess the links between lipid dynamics, reproduction and feeding in these two species and to contribute towards an explanation of the potential causes of the current poor situation of the stocks. The results support the use of fatty acid levels as indicators of the body condition of sardine and anchovy at different reproductive and feeding stages, as well as that of the pelagic environmental conditions. In particular, the relatively low n-3 polyunsaturated fatty acid levels found in spawning sardines compared to spawning anchovies indicate a poorer reproductive health status of sardine. By comparing the current total lipid content values with those recorded in other Mediterranean and North Atlantic areas, and others from more than 10 years ago, in the adjacent area of the Gulf of Lion, our study reveals the persistent poor condition of sardine and anchovy in the northern Catalan Sea. Furthermore, the low levels of diatom fatty acid markers observed throughout the spawning and non-spawning seasons in both sardine and anchovy indicate a diet poor in diatoms. Moreover, the results indicate that it is very unlikely that parasitism is a significant factor in the decline in condition of sardine and anchovy in the northern Catalan Sea. In fact, the results, which we believe provide useful insights for the management of small pelagic fisheries in the Mediterranean, suggest that the current poor condition of sardine and anchovy in the northern Catalan Sea has probably been exacerbated by a decrease in plankton productivity and/or a shift in the taxonomic composition of phytoplankton communities, adding to the ongoing effects of overfishing.

Dietary strategies to improve nutritional value, oxidative stability, and sensory properties of poultry products.

Consumers demand both safer and more nutritious food products exempt of non-natural origin preservatives or other food additives. In this frame, products with lower fat content and/or a higher ratio in unsaturated fatty acids, especially n-3 fatty acids, are desired because these lipids can help prevent the development of cardiovascular and inflammatory pathologies. The intake of meat products is of interest because they are an excellent source of vitamins and minerals. In addition, the shelf-life of meat products can be extended by the presence of natural antioxidants coming from different sources such as plant extracts. Therefore, different strategies have been studied to improve the nutritional value, oxidative stability, and sensory characteristics of meat products and eggs through different mineral and natural dietary supplements. In comparison to other strategies, dietary supplements present the advantage that first the living animals may efficiently distribute the compounds throughout the tissues and second, the dietary supplementation is safer because the resulting enriched meat products and eggs ensure tolerable amounts in humans. Poultry meats and eggs are widely consumed and their fatty acid profile and tocopherol content can be easily modified through different dietary strategies thus being excellent models to improve their nutritional value and oxidative stability.

Effect of high hydrostatic pressure on the oxidation of washed muscle with added chicken hemoglobin.

The role of chicken hemoglobin in lipid oxidation of washed chicken muscle exposed to high hydrostatic pressure (0, 200, 400 and 600 MPa) was examined. The observed decrease in redness was higher with elevated pressures (5.0 vs 3.7). During storage, redness decreased in samples exposed to 400 and 600 MPa. This decrease was concomitant with the progression of oxidation and the 2.5 fold decrease of soluble heme. An additional experiment was conducted to examine the effect of the hemoglobin mode of addition into pressurized muscle. The exposure at 600 MPa led to washed muscle oxidation even in the absence of hemoglobin, thus indicating that pressure treatments triggered lipid oxidation. However, the presence of native or pressurized hemoglobin into pressurized washed muscle caused more hexanal than the pressurized control without hemoglobin. Overall, results suggest that membrane disruption and the release of hemin are crucial for the onset of oxidation.

Zinc-protoporphyrin content in commercial Parma hams is affected by proteolysis index and marbling.

The contents of zinc-protoporphyrin (ZnPP) and heme in twenty-four sliced Parma hams made without the addition of curing agents were determined. Expressed on a dry weight basis, ZnPP averaged 45 mg/kg and ranged from 23 to 85 mg/kg. The heme content averaged 37 mg/kg on a dry matter basis and ranged from 17 to 73 mg/kg. A Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression analyses were carried out to examine the existing correlations between these pigments and various physicochemical parameters in the final product. PCA showed the existence of associations between ZnPP, sensory redness and salt content. PLS suggests that the conversion of ZnPP from heme is facilitated in those hams with a higher proteolysis index and higher marbling.