Combined Strategy Using High Hydrostatic Pressure, Temperature and Enzymatic Hydrolysis for Development of Fibre-Rich Ingredients from Oat and Wheat By-Products.

Wheat bran (WB) and oat hull (OH) are two interesting undervalued cereal processing sources rich in total dietary fibre (TDF) and other associated bioactive compounds, such as ß-glucans and polyphenols. The aim of this study was to optimise a combination chemical (enzymes) and physical (high hydrostatic pressure-temperature) strategies to increase the bioaccessibility of bioactive compounds naturally bound to the bran and hull outer layers. WB and OH were hydrolysed using food-grade enzymes (UltraFloXL and Viscoferm, for WB and OH, respectively) in combination with HPP at different temperatures (40, 50, 60 and 70 °C) and hydrolysis either before or after HPP. Proximal composition, phytic acid, ß-glucans, total phenolics (TPs) and total antioxidant activity (TAC) were evaluated to select the processing conditions for optimal nutritional and bioactive properties of the final ingredients. The application of the hydrolysis step after the HPP treatment resulted in lower phytic acid levels in both matrices (WB and OH). On the other hand, the release of ß-glucan was more effective at the highest temperature (70 °C) used during pressurisation. After the treatment, the TP content ranged from 756.47 to 1395.27 µmol GAE 100 g-1 in WB, and OH showed values from 566.91 to 930.45 µmol GAE 100 g-1. An interaction effect between the temperature and hydrolysis timing (applied before or after HPP) was observed in the case of OH. Hydrolysis applied before HPP was more efficient in releasing OH TPs at lower HPP temperatures (40-50 °C); meanwhile, at higher HPP temperatures (60-70 °C), hydrolysis yielded higher TP values when applied after HPP. This effect was not observed in WB, where the hydrolysis was more effective before HPP. The TP results were significantly correlated with the TAC values. The results showed that the application of optimal process conditions (hydrolysis before HPP at 60 or 70 °C for WB; hydrolysis after HPP at 70 °C for OH) can increase the biological value of the final ingredients obtained.

Effects of Dietary Supplementation with a Ferulic Acid-Rich Bioactive Component of Wheat Bran in a Murine Model of Graft-Versus-Host Disease.

Graft-versus-host disease (GvHD) is a common and severe complication following allogeneic hematopoietic stem cell transplantation (HSCT). Its prevention and treatment is a major challenge. Ferulic acid (FA) has anti-inflammatory and antioxidant properties that could be attractive in this setting. Our aim was to evaluate a bioactive ingredient derived from wheat bran (WB), selected for its high concentration of FA, in a murine model of GvHD. The ingredient was obtained via a bioprocess involving hydrolysis and spray-drying. GvHD was induced via HSCT between MHC-mismatched mouse strains. FA treatment was administered orally. Survival and disease scores (weight loss, hunching, activity, fur texture, and skin integrity, each scored between 0 and 2 depending on disease severity) were recorded daily, histological evaluation was performed at the end of the experiment, and serum inflammatory cytokines were analyzed on days 9 and 28. Treatment with FA did not protect GvHD mice from death, nor did it diminish GvHD scores. However, histological analysis showed that ulcers with large areas of inflammatory cells, vessels, and keratin were less common in skin samples from FA-treated mice. Areas of intense inflammatory response were also seen in fewer small intestine samples from treated mice. In addition, a slight decrease in INF-γ and TNF-α expression was observed in the serum of treated mice on day 28. The results showed some local effect of the ingredient intervention, but that the dose used may not be sufficient to control or reduce the inflammatory response at the systemic level in mice with GvHD. Higher dosages of FA may have an impact when evaluating the immunomodulatory capabilities of the hydrolyzed WB ingredient. Thus, further experiments and the use of technological strategies that enrich the ingredients in soluble ferulic acid to improve its efficacy in this setting are warranted.

Study of the Total Antioxidant Capacity (TAC) in Native Cereal-Pulse Flours and the Influence of the Baking Process on TAC Using a Combined Bayesian and Support Vector Machine Modeling Approach.

During the last few years, the increasing evidence of dietary antioxidant compounds and reducing chronic diseases and the relationship between diet and health has promoted an important innovation within the baked product sector, aiming at healthier formulations. This study aims to develop a tool based on mathematical models to predict baked goods' total antioxidant capacity (TAC). The high variability of antioxidant properties of flours based on the aspects related to the type of grain, varieties, proximal composition, and processing, among others, makes it very difficult to innovate on food product development without specific analysis. Total phenol content (TP), oxygen radical absorbance capacity (ORAC), and ferric-reducing antioxidant power assay (FRAP) were used as markers to determine antioxidant capacity. Three Bayesian-type models are proposed based on a double exponential parameterized curve that reflects the initial decrease and subsequent increase as a consequence of the observed processes of degradation and generation, respectively, of the antioxidant compounds. Once the values of the main parameters of each curve were determined, support vector machines (SVM) with an exponential kernel allowed us to predict the values of TAC, based on baking conditions (temperature and time), proteins, and fibers of each native grain.

Valorisation of Buckwheat By-Product as a Health-Promoting Ingredient Rich in Fibre for the Formulation of Gluten-Free Bread.

Bread is a widely consumed food that has often been used as a vehicle for functional ingredients such as dietary fibre. Fibre-rich breads have beneficial physiological effects on health, helping to combat chronic pathologies such as cardiovascular disease, diabetes, and certain types of colon cancer. The aim of this study is to evaluate the technological and nutritional effects of the inclusion of buckwheat hull particles (BH) at two addition levels (3 and 6%) and two particle sizes (fine, D50: 62.7 µm; coarse, D50: 307 µm) in a gluten-free (GF) bread formulation. A significant (p < 0.05) increase in the dough elastic modulus (G') was observed for all doughs containing BH, from 712 Pa for a rice-based dough to 1027-3738 Pa for those containing BH. Compared to rice-based breads, those containing BH showed a significant (p < 0.05) increase in total dietary fibre content (from three to five times) and in antioxidant capacity (from 78 to 290 mg TE/100 g dw. in the ORAC test). Breads containing fine BH at a level of 3% had similar sensory properties to the rice-based bread, demonstrating that it is possible to improve the TDF content while maintaining the sensory quality of the GF bread.

Antioxidant, Immunostimulatory, and Anticancer Properties of Hydrolyzed Wheat Bran Mediated through Macrophages Stimulation.

Previous studies demonstrated that enzymatic hydrolysis enhances wheat bran (WB) biological properties. This study evaluated the immunostimulatory effect of a WB hydrolysate (HYD) and a mousse enriched with HYD (MH) before and after in vitro digestion on murine and human macrophages. The antiproliferative activity of the harvested macrophage supernatant on colorectal cancer (CRC) cells was also analyzed. MH showed significantly higher content than control mousse (M) in soluble poly- and oligosaccharides (OLSC), as well as total soluble phenolic compounds (TSPC). Although in vitro gastrointestinal digestion slightly reduced the TSPC bioaccessibility of MH, ferulic acid (FA) levels remained stable. HYD showed the highest antioxidant activity followed by MH, which demonstrated a greater antioxidant activity before and after digestion as compared with M. RAW264.7 and THP-1 cells released the highest amounts of pro-inflammatory cytokines after being treated with 0.5 mg/mL of digested WB samples. Treatment with digested HYD-stimulated RAW264.7 supernatant for 96 h showed the most anticancer effect, and spent medium reduced cancer cell colonies more than direct WB sample treatments. Although a lack of inner mitochondrial membrane potential alteration was found, increased Bax:Bcl-2 ratio and caspase-3 expression suggested activation of the mitochondrial apoptotic pathway when CRC cells were treated with macrophage supernatants. Intracellular reactive oxygen species (ROS) were positively correlated with the cell viability in CRC cells exposed to RAW264.7 supernatants (r = 0.78, p < 0.05) but was not correlated in CRC cells treated with THP-1 conditioned media. Supernatant from WB-stimulated THP-1 cells may be able to stimulate ROS production in HT-29 cells, leading to a decrease of viable cells in a time-dependent manner. Therefore, our present study revealed a novel anti-tumour mechanism of HYD through the stimulation of cytokine production in macrophages and the indirect inhibition of cell proliferation, colony formation, and activation of pro-apoptotic proteins expression in CRC cells.

Impact of Protein Content on the Antioxidants, Anti-Inflammatory Properties and Glycemic Index of Wheat and Wheat Bran.

Conventional wheat milling generates important volumes of wheat bran (WB), which is a concentrated source of polyphenols and insoluble fiber. In terms of health benefits and based on epidemiological and experimental evidence, these compounds contribute to reducing the risk of certain chronic pathologies. Protein concentration is the main quality factor conditioning wheat use in the agroindustry. When turning waste into feasible resources, it is essential to evaluate the variability of the raw material. The aim of this study was the evaluation of the impact of protein content in the valorization of WB based on its antioxidants, anti-inflammatory properties and glycemic index (GI). A significantly (p ≤ 0.05) lower content of phenolic compounds was found in the whole grain (WG) fractions, both free (FP) and bound (BP), as compared to the WB phenolic fractions, differences that ranged from 4- to 6-fold (538 to 561 mg GAE 100 g-1 in WG vs. 1027 to 1236 in WB mg GAE 100 g-1 in FP and 2245 to 2378 vs. 6344 to 7232 mg GAE 100 g-1 in BP). A significant (p ≤ 0.05) effect of the protein content on the resulting phenolic content and antioxidant capacity was observed, especially in WG, but also in WB, although in the latter a significant (p ≤ 0.05) negative correlation was observed, and increasing the protein content resulted in decreasing total phenolic content, antioxidants, and ferric-reducing capacities, probably due to their different types of proteins. The highest protein content in WB produced a significant (p ≤ 0.05) reduction in GI value, probably due to the role of protein structure in protecting starch from gelatinization, along with phytic acid, which may bind to proteins closely associated to starch and chelate calcium ions, required for α-amylase activity. A significant (p ≤ 0.05) effect of the protein content on the GI was also found, which may be explained by the structural effect of the proteins associated with starch, reducing the GI (21.64). The results obtained show the importance of segregation of WB in valorization strategies in order to increase the efficiency of the processes.

Antioxidant, Antihypertensive, Hypoglycaemic and Nootropic Activity of a Polyphenolic Extract from the Halophyte Ice Plant (Mesembryanthemum crystallinum).

This study aims to determine the potential antioxidant, antihypertensive, hypoglycaemic and nootropic activity of a purified polyphenolic extract from the halophyte ice plant (Mesembryanthemum crystallinum). The ice plant extract showed good antioxidant activity measured by DPPH, ORAC, TEAC, FRAP and ferrous ion chelating activity. Moreover, the extract showed potent ACE, DPP-IV and PEP-inhibitory activity (90.5%, 98.6% and 73.1%, respectively, at a final concentration of 1 mg/mL). The extract was fractionated and the fraction with the highest content of total phenolic compounds showed the highest bioactivity, suggesting that polyphenols could be mainly responsible for the abovementioned activities. The tentative polyphenol identification by HPLC-ESI-QTOF-MS in this fraction revealed that flavones (>65%) are the major group, with apigenin (38%) predominating, followed by diosmin (17.7%) and luteolin (11.9%). They could presumably be the main elements responsible for the enzymatic inhibition activity. Additionally, 4-hydroxybenzoic acid, p-coumaric acid and a hydroxycinnamic acid derivative (2-O-(p-cumaroyl)-l-malic acid) were found in the extract. To our knowledge, this is the first time that some of these activities have been reported for halophyte extracts.

Pulse-Cereal Blend Extrusion for Improving the Antioxidant Properties of a Gluten-Free Flour.

Extrusion is an interesting technological tool that facilitates pulse formulation into flour mixtures, with tailored fibre content, total antioxidant capacity (TAC) and glycemic index (GI) among other components in final formulas. The gluten-free (GF) market has significantly grown during the last years. GF products have evolved from specialty health foods to products targeted to the general population and not only associated to celiac consumers. This study evaluates how temperature, cereal base (rice/corn) and pulse concentration affect extruded flour properties and which conditions are more efficient to develop a gluten-free flour with high TAC and low GI. Additionally, it evaluated the effect of this optimal formula after the baking process. The results showed an increase of total phenol (TP) and antioxidant activity with extrusion, with a temperature-dependent effect (130 °C ≥ 120 °C ≥ 110 °C), which may imply an enhanced bioaccessibility of phenolics compounds after extraction. Extrusion increased GI in comparison to native flour; however, a dough temperature of 130 °C resulted in a significantly (p ≤ 0.05) lower GI than that observed for 110-120 °C doughs, probably associated to the pastification that occurred at higher temperatures, which would decrease the degree of gelatinization of the starches and therefore a significant (p ≤ 0.05) GI reduction. Corn-lentil flour showed higher antioxidant properties and lower GI index in comparison with rice-lentil blends. The formulation of the optimal blend flour into a baked product (muffin) resulted in a significant loss of antioxidant properties, with the exception of the reducing power (FRAP), although the final antioxidant values of the baked product were in the range of the original native flour blend before any process.

Wheat and Oat Brans as Sources of Polyphenol Compounds for Development of Antioxidant Nutraceutical Ingredients.

Bran, a byproduct still mainly used for animal feed, is receiving increased attention as potential ingredient for a healthier diet. The aim of this study was to characterize and evaluate the nutritional and antioxidant properties of wheat and oat bran in order to promote their use as nutraceutical ingredients in flour and/or other products. The effects of grain (wheat vs. oat) and milling fraction (whole grain vs. bran) on the phenolic profile (free vs. bound phenolics), antioxidant and nutrient profiles, and glycemic index were evaluated. Differences in antioxidant capacity through different methodologies between grain and bran were observed, supporting a higher in vitro antioxidant capacity of the whole grain than that of the refined flours, which lack the bran fraction. The highest RACI (Relative Antioxidant Capacity Index) corresponded to wheat bran bound fraction, which showed the highest concentration of ferulic acid and correlation with antioxidant parameters tested. The in vitro glycemic index of the bran fractions was reduced, as compared with grain, with lower values found for wheat. The results support the important benefits of the polyphenols linked to fiber and the importance to develop methods to increase bioavailability of these compounds, which would promote WB use as nutraceutical ingredient.

Bioprocessed Wheat Ingredients: Characterization, Bioaccessibility of Phenolic Compounds, and Bioactivity During in vitro Digestion.

To enlarge the applications of whole wheat grain (WWG) and wheat bran (WB) as functional ingredients in foodstuffs that can promote human health, researchers have explored bioprocessing approaches to improve the bioaccessibility of phenolic compounds from these food matrices and, subsequently, their biological effects. The objective of this study was to compare the composition in nutrients, anti-nutrients, and bioactive compounds of WWG and WB, and their respective bioprocessed products: sprouted wheat (GERM) and WB hydrolysate (stabilized by spray-drying [SPD] and microencapsulated [MEC]). In addition, to evaluate the functional properties of these ingredients, the bioaccessibility of phenolic compounds and their potential antioxidant and anti-inflammatory activities were monitored in different digestion steps. GERM had increased amounts of insoluble dietary fiber, higher diversity of oligosaccharides, and higher concentration of monosaccharides, free phosphorous, and phenolic compounds than WWG. SPD had improved content of soluble dietary fiber, oligosaccharides, monosaccharides, free phosphorous, and phenolic compounds (vs. WB), whereas MEC was mainly composed of protein and had nearly 2-fold lower content of SPD components. All the ingredients showed lower amounts of phytic acid as compared with raw materials. In all samples, hydroxycinnamic acids were the most representative polyphenols followed by minor amounts of hydroxybenzoic acids and flavonoids. Gastrointestinal digestion of GERM, SPD, and MEC revealed high stability of total phenolic compounds in both gastric and intestinal phases. Hydroxycinnamic acids were the most bioaccessible compounds during digestion among the three bioprocessed wheat ingredients studied, although their bioaccessibility varied across ingredients. In this sense, the bioaccessibility of ferulic acid (FA) derivatives increased in GERM with progression of the digestion, while it was reduced in SPD and MEC up to the end of the intestinal phase. Microencapsulation of SPD with pea protein led to generally to lower bioaccessible amounts of phenolic acids. Comparison analysis of biological effects highlighted SPD for its most potent antioxidant effects in the gastrointestinal tract (3 out 4 antioxidant parameters with highest values), while no clear differences were observed with regard to in vitro anti-inflammatory activity. Overall, these results support the potential application of GERM, SPD, and MEC as functional and nutraceutical ingredients.

Exploring the potential of common iceplant, seaside arrowgrass and sea fennel as edible halophytic plants.

The recent interest in diversification in food consumption and the current salinization and desertification processes of farmland have placed the focus on halophytic plants as new food, making necessary the characterization of their biochemical composition and the identification of possible bioactive compounds. In this work, three edible halophytic plants were characterized: common iceplant (Mesembryanthemum crystallinum), sea fennel (Crithmum maritimum), and seaside arrowgrass (Triglochin maritima). The plants studied were a good source of minerals. Sea fennel showed high contents of dietary fibre and calcium (8.5 ppm, wet weight), common iceplant had a high potassium content (6500 ppm, wet weight), while seaside arrowgrass presented high levels of iron (62 ppm, wet weight). The glucose content of the three species was below 30 mg/g per dried weight. The Sb, Pb, Cr, As, Cd, and Hg content was negligible. Polyunsaturated fatty acids, mainly α-linolenic and linoleic acid, prevailed in the three species analyzed. Hydroxycinnamic and hydroxybenzoic acids predominated in common iceplant and sea fennel. Glycosylated flavones, especially isoorientin, prevailed in seaside arrowgrass. These plants present a relevant nutritional profile for which their use as foods or ingredients should be promoted.

Effects of a snack enriched with carob and Undaria pinnatifida (wakame) on metabolic parameters in a double blind, randomized clinical trial in obese patients.

INTRODUCTION: Introduction: the composition of snack foods likely influences the overall effect that snacking has on metabolism and obesity. The objective of the current study was to assess the responses to two different snacks, one of them supplemented with wakame and carobs, on cardiovascular risk factors, satiety, and subsequent food intake in obese subjects with metabolic syndrome. Material and Methods: forty patients were randomized in a clinical trial (NCT03420989, clinicaltrial.gov) to group I (enriched snack, n = 16) or group II (control snack, n = 16). At baseline and after 8 weeks biochemical parameters, dietary intakes, and nutritional status were assessed. The subjects also rated their feelings of satiety/hunger with a test meal. Results: no differences were detected in anthropometric parameters between both snacks. Changes in other parameters were detected in patients with enriched snacks, with a significant decrease in LDL-cholesterol by 7.4 % (intervention snack, -8.9 ± 2.3 mg/dL vs control snack, -0.9 ± 3.3 mg/dL; p = 0.03), in total cholesterol by 5.8 % (intervention snack, -10.4 ± 2.9 mg/dL vs control snack, -1.4 ± 3.2 mg/dL; p = 0.02), and in resistin level by 15.9 % (intervention snack, -1.0 ± 0.2 mg/dL vs control snack, -0.1 ± 0.3 mg/dL: p = 0.03). After the test meal, satiety scores (after 20 min and 40 min) were higher than fasting levels in both groups. The same results were obtained with the 100-mm, 5-point visual satiety scale. Conclusion: our study indicates that a wakame- and carob-enriched snack induces a significant decrease in total cholesterol, LDL-cholesterol, and resistin levels when compared to a control snack, without effects on food consumption, other cardiovascular parameters, or anthropometric parameters.

INTRODUCCIÓN: Introducción: la composición de los "snacks" probablemente influya en el efecto que produce su consumo sobre los marcadores metabólicos y la obesidad. El objetivo fue evaluar respuestas a dos snacks, uno de ellos suplementado con wakame y algarroba, sobre factores de riesgo cardiovascular, saciedad y posterior ingesta de alimentos, en sujetos obesos con síndrome metabólico. Material y métodos: se aleatorizaron 40 pacientes en el ensayo clínico NCT03420989 (clinicaltrial.gov) para participar en el grupo I (snack enriquecido, n = 16) o el grupo II (snack de control, n = 16). Antes y después de 8 semanas se determinaron parámetros bioquímicos, ingestas dietéticas y estado nutricional. A los sujetos también se les evaluó saciedad y apetito con comida de prueba. Resultados: no se detectaron diferencias en parámetros antropométricos con ambos snacks. Se detectaron cambios en parámetros bioquímicos de pacientes que recibieron snacks enriquecidos, con disminución significativa del colesterol-LDL del 7,4 % (snack de intervención, -8,9 ± 2,3 mg/dl vs. snack de control, -0,9 ± 3,3 mg/dl; p = 0,03), del colesterol total del 5,8 % (snack de intervención, -10,4 ± 2,9 mg/dl vs. snack de control, -1,4 ± 3,2 mg/dl; p = 0,02) y de niveles de resistina del 15,9 % (snack de intervención, -1,0 ± 0,2 mg/dl vs. snack de control, -0,1 ± 0,3 mg/dl; p = 0,03). Después de la comida de prueba, las puntuaciones de saciedad (a los 20 min y 40 min) fueron más altas que nivel de ayuno en ambos grupos. Los resultados fueron similares con escala de saciedad visual de 5 puntos y 100 mm. Conclusión: nuestro estudio muestra que un snack enriquecido con wakame y algarroba produce disminución significativa de los niveles de colesterol total, colesterol-LDL y resistina frente a un snack de control, sin efectos sobre el consumo de alimentos, otros parámetros cardiovasculares y los parámetros antropométricos.

Soluble Phenolic Composition Tailored by Germination Conditions Accompany Antioxidant and Anti-inflammatory Properties of Wheat.

Knowledge on the specific variation in the phenolic composition of wheat defined by germination conditions and its relationship with antioxidant and anti-inflammatory properties of sprouts would be useful to improve the functional value of wheat-derived products. Variation in soluble phenolic composition, antioxidant and anti-inflammatory potential of wheat was examined in a range of germination temperature (12-21 °C) and time (1-7 d). Response surface methodology was applied for building lineal and quadratic models to find optimal germination conditions to improve nutraceutical value of wheat sprouts using the desirability (D) function. Phenolics were determined by HPLC-DAD-ESI-MS. In vitro biochemical methods and lipopolysaccharide stimulated RAW264.7 macrophages were used to determine antiradical and anti-inflammatory activities of wheat sprouts. Accumulation of soluble phenolic acids, flavone C-glycosides and lignans in sprouts was positively influenced by germination temperature and time. Increased concentration of individual polyphenols was directly associated with improved ability of sprouts for radical scavenging and reduction of tumor necrosis factor α and interleukin 6 in macrophages. Optimal desirability (D = 0.89) for improved nutraceutical value of wheat sprouts was achieved at 21 °C for 7 d. This information would be useful for food industry aiming at producing wheat-based products with better nutritional and healthy properties.

Effects of dietary inclusions of red beet and betaine on the acute stress response and muscle lipid peroxidation in rainbow trout.

This study evaluates the effects of red beet (RB) and betaine on rainbow trout submitted to an acute stress challenge. A control diet was compared with four experimental diets in which red beet (14 and 28%) and betaine (0.9 and 1.63%) were incorporated in different concentrations according to a factorial design. Cortisol in plasma and fin, glucose and lactate plasma levels, and malondialdehide (MDA) in muscle were all measured before the stress challenge and 30 min and 6 and 12 h after the stress challenge as parameters to determine the diet effects. RB and betaine had no effect on cortisol, glucose, and MDA basal levels. However, lactate basal levels were significantly lower on fish fed with RB and betaine. Thirty minutes after the stress challenge, there was a significant increase in plasma and fin cortisol, glucose and lactate concentrations, although fish fed with diets containing RB and betaine showed significantly higher plasma cortisol values. MDA values of fish fed with 14% RB and 0.9% betaine were significantly higher than MDA values from fish fed with 28% RB and 1.63% betaine. After 6 and 12 h, plasma and fin cortisol and lactate levels recovered in a similar trend. Glucose plasma levels recovered in almost all groups 12 h after the stress. Also, MDA values recovered basal levels after 6 and 12 h. RB and betaine did not enhance the tolerance to the stress challenge compared to the control group, although the presence of these ingredients had no negative effect on any of the stress indicators.

Red beet and betaine as ingredients in diets of rainbow trout (Oncorhynchus mykiss): effects on growth performance, nutrient retention and flesh quality.

The objective of the study was to evaluate the impact of different concentrations of dietary red beet and betaine on the growth performance and fish flesh quality of rainbow trout. Therefore, a control diet was compared with four diets in which two levels of red beet (14% and 28%) and betaine (0.9% and 1.63%) were incorporated in combination. The study was set up with an average body weight of 69 ± 2.2 g and finished when fish reached commercial weight (175-250 g) after 105 d. The impact of the diets was studied based on the growth performance, biometric indexes, proximal composition, protein and fat retention efficiencies and apparent nutrient digestibility by fish reared on a recirculation system. Further estimates were the effect of red beet and betaine on the flesh proximate composition and quality of the final product (water activity, colour, texture, thiobarbituric acid reactive substances and sensory characteristics). Results showed that inclusion of 14% red beet and 0.9% betaine did not affect growth, nutritive or biometric parameters and nutrient retention when compared with the control diet. However, higher levels of red beet and betaine had negative effects on growth and nutritive parameters. The tested ingredients enhanced quality parameters regardless of the concentration used. After feeding the red beet and betaine, fish flesh showed lower water activity and better textural and colour properties than the control and also a dose-dependent effect on lipid oxidation was observed.

Structure elucidation of ACE-inhibitory and antithrombotic peptides isolated from mackerel skin gelatine hydrolysates.

BACKGROUND: The fish-processing industry generates significant amounts of waste and by-products that are usually discarded. This study investigated the preparation of bioactive gelatine peptides from fish skin. Gelatine was extracted from mackerel (Scomber scombrus) skin and hydrolysed by pepsin for 1, 2, 6 and 24 h. All hydrolysates were screened for antioxidant, ACE-inhibitory and antithrombotic activities. RESULTS: Gelatine peptides obtained after 24 h of hydrolysis exhibited the highest antioxidant activity (DPPH reduction ∼80%, FRAP ∼130 µmol Trolox equivalent L(-1) ). These hydrolysates had high ACE-inhibitory activity (>70%) and were able to significantly (P < 0.05) inhibit platelet aggregation by about 30%, corresponding to moderate antithrombotic activity. CONCLUSION: The bioactive properties were mainly due to the presence of low-molecular-weight peptides of 337 and 423 Da.

Effect of heat shock on browning-related enzymes in minimally processed iceberg lettuce and crude extracts.

The effects of heat shock on PPO and POD activity in minimally processed Iceberg lettuce was examined during storage (10 days). The results were compared with the effect of temperature on crude extracts of these enzymes (in vitro analysis). Fresh-cut lettuce washed at 50 degrees C showed significantly lower PPO and POD activity throughout storage than lettuce washed at 4 degrees C and 25 degrees C. These results were consistent with a sensory analysis in which the panellists found the lowest browning scores in those samples treated at 50 degrees C. When PPO and POD were analysed in vitro, the samples treated at 50 degrees C showed a rapid loss of POD activity and a similar but slower loss of PPO activity in all tissues, while incubation at 4 degrees C and 25 degrees C showed no significant loss of activity. While heat shock did not lead to significant loss of activity it did repress the synthesis of PPO and POD during storage.