Dietary Spirulina (Arthrospira platensis) and Thyme (Thymus vulgaris) supplementation to growing rabbits: Effects on raw and cooked meat quality,nutrient true retention and oxidative stability

The study evaluated the effect of Spirulina and Thyme dietary supplementation on rabbit meat quality, nutrient true retention and protection against oxidative stress. Rabbits in the control group (C–C) received a non-supplemented pellet throughout the experiment (5–11 weeks of age). In the other groups, the pellet contained 5% Spirulina (S), 3% Thyme (T), or both (ST) for either the entire (groups S–S, T–T, ST–ST) or only the final part of the growing period (8–11 weeks: groups C–S, C–T, C–ST). Spirulina supplementation increased the γ-linolenic acid content of rabbit meat, whereas Thyme improved the oxidative stability of raw and freeze-dried meat.     

Effect of housing conditions on production,carcass and meat quality traits of growing rabbits

Production, carcass traits and meat quality of rabbits housed in cages or in different pens were compared. Rabbits (n = 579) were sorted into 5 groups: C = cage (2 rabbits/cage); pen without platform: P11 = 9 rabbits/pen; P16 = 14 rabbits/pen; pen with platform: PW = wire net platform, 14 rabbits/pen; PD = platform with straw-litter, 14 rabbits/pen. Feed intake and average daily gain between 5 and 11 weeks, and body weight at 11 weeks were significantly higher in C rabbits than that of the mean of pen-housed groups, while the PD group had the lowest growth performance. C rabbits had the smallest hind part to reference carcass (P < 0.001) and the largest percentage of perirenal and scapular fat (P < 0.001). The meat/bone ratio was the largest in group C (P < 0.05). Differences were recorded in a* value and lipid content of m. Longissimus dorsi. Rabbits housed in cages generally had the best performance whereas those housed in pens with platform exhibited the worst.     

Bio-nutritional evaluations of three tropical leaf vegetables (Telfairia occidentalis, Amaranthus cruentus and Talinum triangulare) as sole dietary protein sources in rat assay

The bio-nutritional potentials of three tropical vegetable leaf meals (Telfairia occidentalis leaf meal, TOLM; Talinum triangulare leaf meal, TTLM and Amaranthus cruentus leaf meal, ACLM) were investigated using albino rat as the test animal. Some protein quality evaluation indices were measured when the three vegetable leaf meals (VLMs) were used as sole protein sources in diets fed to the experimental animals and results were compared with data obtained for a basal nitrogen free diet (diet 1) and another reference diet (diet 2) in which the protein was solely supplied by nutritional casein (pure protein). The weight gain value recorded over a 10 day experimental period for the test animals on the reference (casein) diet 2 was consistently higher (P < 0.05) than the weight gain value obtained for the animals on the 3 VLMs diets (diets 3–5). Feed intake values recorded for the rats on the VLMs were similar (P > 0.05) and significantly higher (P < 0.05) than the value obtained for rats on the reference (casein) diet. Nitrogen excreted in faeces (feacal nitrogen) was lowest (P < 0.05) for the animals in reference diet 2. However, the nitrogen excreted in urine (urinary nitrogen) was highest (P < 0.05) for the animals on reference diet 2 and lowest for animals on diet 3 (TOLM diet) (P < 0.05). The nitrogen retention (NR) value obtained for the test animals on the reference diet 2 was similar (P > 0.05) to the value obtained for animals on diet 3 (TOLM). These values were significantly higher (P > 0.05) than NR values obtained for animals on diets 4 (TTLM) and 5 (ACLM). Expectedly, the apparent nitrogen digestibility (AND), protein efficiency ratio (PER), net protein ratio (NPR), true digestibility (TD), biological value (BV) and net protein utilization (NPU) all indicated higher and better values (P < 0.05) than the corresponding values obtained for the 3 VLMs diets (diets 3–5).     

Addition of seaweed (Laminaria digitata) extracts containing laminarin and fucoidan to porcine diets: Influence on the quality and shelf-life of fresh pork

A seaweed extract containing laminarin (L) and fucoidan (F) (L/F) was manufactured from brown seaweed (Laminaria digitata) in spray-dried (L/F-SD) and wet (L/F-WS) forms. The effect of supplementation of pig diets with L/F-SD and L/F-WS (L, 500 mg/kg feed; F, 420 mg/kg feed) for 21 days pre-slaughter, on quality indices of fresh M. longissimus dorsi (LD) steaks was examined. Susceptibility of porcine liver, heart, kidney and lung tissue homogenates to iron-induced (1 mM FeSO₄) lipid oxidation was also investigated. Dietary supplementation with L/F did not increase plasma total antioxidant status (TAS). In LD steaks stored in modified atmosphere packs (80% O₂:20% CO₂) (MAP) for up to 15 days at 4 °C, muscle pH, surface colour (CIE ‘L*’ lightness, ‘a*’ redness and ‘b*’ yellowness values) and microbiology (psychrotrophic and mesophilic counts, log CFU/g pork) were unaffected by dietary L/F. In general, levels of lipid oxidation (TBARS, mg MDA (malondialdehyde)/kg pork) followed the order: C > LF-SD > L/F-WS. A statistically significant reduction in lipid oxidation (P < 0.05) was observed in LD steaks from 75% of pigs (n = 6) fed with L/F-WS compared to controls. Iron-induced lipid oxidation increased in liver, heart, kidney and lung tissue homogenates over the 24 h storage period and dietary L/F-WS reduced lipid oxidation to the greatest extent in liver tissue homogenates. Results demonstrate potential for the incorporation of marine-derived bioactive antioxidant components into muscle foods via the animal's diet.     

Meat quality attributes of the Longissimus lumborum muscle of the Kh'ara genotype of llama (Lama glama) reared extensively in northern Chile

Twenty male llama of the Kh'ara genotype, reared extensively in the north of Chile, were slaughtered at ages between 2 and 4 permanent teeth (2 to 3.5 years) and analyses were carried out on the Longissimus lumborum muscle, including composition (moisture, fat, protein, ash, cholesterol, amino acids, fatty acid profile and collagen content) and meat quality parameters (pH, color, water holding capacity and Warner–Bratzler shear-force). Llama meat was characterized by a low cholesterol (39.04 mg/100 g) and intramuscular fat (1.56%) content, a total collagen content of 6.28 mg/g, of which 20.28% was soluble collagen. Amino acid composition and fatty acid profile were similar to those found for beef finished on forage. Llama meat showed a low n − 6/n − 3 (4.69) and hypocholesterolemic/hypercholesterolemic (1.55) ratio and acceptable values of DFA (65.78%). Quality parameters in llama Longissimus muscle were within the ranges reported for more traditional meats such as beef and lamb.     

Meat quality,proximate composition and muscle fatty acid profile of young llamas (Lama glama) supplemented with hay or concentrate during the dry season

Thirty llamas were used to study the effect of a 90 day feed supplementation on meat quality, chemical composition and muscle fatty acid profile. Treatments were: GR = llama on native pasture until slaughter; GR + SH = like GR, but with overnight free access to barley/alfalfa hay; and GR + SC = like GR, but with overnight free access to a wheat bran/sorghum grain concentrate. The supplementation had no effect on postmortem pH and temperature decline in the Longissimus lumborum muscle (LLM), cooking losses nor Warner–Bratzler shear force values (P > 0.05). Meat from GR + SC llama had higher fat content in LLM (P < 0.05) compared to GR and GR + SH llama. Intramuscular fat from GR + SH llama showed higher (P < 0.01) proportions of polyunsaturated fatty acids, higher (P < 0.05) polyunsaturated fatty acids/saturated fatty acids and desirable fatty acids ratio, lower (P < 0.05) omega-6/omega-3 (n − 6/n − 3) ratio, and higher (P < 0.01) conjugated linoleic acid.     

Effect of low voltage electrical stimulation on biochemical and quality characteristics of Longissimus thoracis muscle from one-humped Camel (Camelus dromedaries)

The effects of electrical stimulation (90 V) 20 min post mortem on meat quality and muscle fibre types of four age group camels (1–3, 4–6, 7–9, 10–12 years) camels were assessed. Quality of the Longissimus thoracis at 1 and 7 days post mortem ageing was evaluated using shear force, pH, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss and L^∗, a^∗, b^∗ colour values. Age of camel and electrical stimulation had a significant effect on meat quality of L. thoracis. Electrical stimulation resulted in a significantly (P < 0.05) more rapid pH fall in muscle during the first 24 h after slaughter. Muscles from electrically-stimulated carcasses had significantly (P < 0.05) lower pH values, longer sarcomeres, lower shear force value, higher expressed juice and myofibrillar fragmentation index than those from non-stimulated ones. Electrically-stimulated meat was significantly (P < 0.05) lighter in colour than non-stimulated based on L^∗ value. Muscles of 1–3 year camels had a significantly (P < 0.05) lower shear force value, and pH, but longer sarcomere, and higher myofibrillar fragmentation index, expressed juice, and lightness colour (L^∗) than those of the 10–12 years camels. The proportions of Type I, Type IIA and Type IIB were 25.0, 41.1 and 33.6%, respectively were found in camel meat. Muscle samples from 1–3 year camels had significantly (P < 0.05) higher Type I and lower Type IIB fibres compared to those from 10–12 year camel samples. These results indicated that age and ES had a significant effect on camel meat quality.     

In vitro and in vivo protein hydrolysis of beans (Phaseolus vulgaris) genetically modified to express different phaseolin types

Experiments were conducted to study whether phaseolin type could influence proteolysis susceptibility and nutritional value of total bean protein. The DOR-390 bean cultivar was genetically modified to express different phaseolin types (S, T or I). Beans were soaked and autoclaved. A sequential hydrolysis was carried out in vitro with pepsin and pancreatin. Differences in the degree of protein hydrolysis among bean lines started at 30 min and remained until 240 min, with the S bean proteins presenting lower values (P < 0.05). Subsequently, rats were fed with diets containing beans expressing different phaseolin types as the only source of protein for N digestibility and nutritional value determination. No differences (P > 0.05) in ileal protein digestibility and rat growth were observed. In conclusion, the differences in in vitro hydrolysis between bean lines expressing different phaseolin types had no consequences on growth and N retention in rats.     

The survivability of Bacillus anthracis (Sterne strain) in processed liquid eggs

In this study, we investigated the survival and inactivation kinetics of a surrogate strain of Bacillus anthracis (Sterne strain) in whole egg (WE), egg white (EW), sugared egg yolk (YSU), and salted egg yolk (YSA) at low (−20, 0, and 5 °C), moderate (15, 20, 25, 30, 35, and 40 °C), and high storage temperatures (45, 50, 55, and 60 °C). Outgrowth of the spores was measured as lag phase duration (LPD). Replication of vegetative cells was measured in terms of growth rate (GR) and maximum population density (MPD). Spore inactivation was recorded as inactivation rate and percent reduction in viable count. In general, spore viability decreased at low and high temperatures and increased at moderate temperatures. At 0 and 5 °C, a 60–100% reduction in spore viability was seen within 2–3 weeks in WE and YSU, 0–30% in YSA, and 50–100% in EW. At −20 °C, however, no drop in spore titer was observed in YSU and EW but a 20% drop in titer was seen in YSA and 50% in WE within 2–3 weeks. At high temperatures, WE, EW, and YSA produced a 20–50% drop in the spore titer within 1–4 h whereas YSU showed 100% inactivation within 0.75 h. At moderate storage temperatures, as the temperature increased from 15 to 40 °C, LPD decreased from 13.5 to 0.75 h and MPD reached 0.27–2.2 × 10⁹ CFU/ml in YSU and WE, respectively. Markedly lower growth was observed in YSA (LPD = 24–270 h, MPD = 9 × 10⁵ CFU/ml) and spores were inactivated completely within 1–6 h in EW. The survivability and inactivation data of B. anthracis in liquid egg products reported in this investigation will be helpful in developing risk assessment models on food biosecurity.     

Lipid content and fatty acid profile of Senegalese sole (Solea senegalensis Kaup, 1858) juveniles as affected by feed containing different amounts of plant protein sources

A growth trial with Senegalese Sole (Solea senegalensis Kaup, 1858) juveniles fed with diets containing increasing replacement levels of fishmeal by mixtures of plant protein sources was conducted over 12 weeks. Total fat contents of muscle, liver, viscera, skin, fins and head tissues were determined, as well as fatty acid profiles of muscle and liver (GC-FID analysis). Liver was the preferential local for fat deposition (5.5–10.8% of fat) followed by fins (3.4–6.7% fat). Increasing levels of plant protein in the diets seems to be related to increased levels of total lipids in the liver. Sole muscle is lean (2.4–4.0% fat), with total lipids being similar among treatments. Liver fatty acid profile varied significantly among treatments. Plant protein diets induced increased levels of C16:1 and C18:2 n−6 and a decrease in ARA and EPA levels. Muscle fatty acid profile also evidenced increasing levels of C18:2 n−6, while ARA and DHA remained similar among treatments. Substitution of fishmeal by plant protein is hence possible without major differences on the lipid content and fatty acid profile of the main edible portion of the fish – the muscle.     

Identification of single nucleotide polymorphisms in the bovine solute carrier family 11 member 1 (SLC11A1) gene and their association with infection by Mycobacterium avium subspecies paratuberculosis

Johne's disease is a chronic enteritis caused by Mycobacterium avium ssp. paratuberculosis (MAP) that causes substantial financial losses for the cattle industry. Susceptibility to MAP infection is reported to be determined in part by genetic factors, so marker-assisted selection could help to obtain bovine populations that are increasingly resistant to MAP infection. Solute carrier family 11 member 1 (SLC11A1) was adjudged to be a potential candidate gene because of its role in innate immunity, its involvement in susceptibility to numerous intracellular infections, and its previous association with bovine MAP infection. The objectives of this study were to carry out an exhaustive process of discovery and compilation of polymorphisms in SLC11A1 gene, and to perform a population-based genetic association study to test its implication in susceptibility to MAP infection in cattle. In all, 57 single nucleotide polymorphisms (SNP) were detected, 25 of which are newly described in Bos taurus. Twenty-four SNP and two 3′-untranslated region polymorphisms, previously analyzed, were selected for a subsequent association study in 558 European Holstein-Friesian animals. The SNP c.1067C > G and c.1157-91A > T and a haplotype formed by these 2 SNP yielded significant association with susceptibility to MAP infection. The c.1067C > G is a nonsynonymous SNP that causes an amino acid change in codon 356 from proline to alanine (P356A) that could alter SLC11A1 protein function. This association study supports the involvement of SLC11A1 gene in susceptibility to MAP infection in cattle. Our results suggest that SNP c.1067C > G may be a potential causal variant, although functional studies are needed to assure this point.     

Application of microwaves dielectric spectroscopy for controlling pork meat (Longissimus dorsi) salting process

Salting treatment is a common operation in the production of high quality meat products, one of its main problems is the difficulty to control the simultaneous water and salt fluxes into the product and control the protein fibers transformation throughout process. Dielectric properties of salted porcine meat are strongly related to its structure and composition. Thus, dielectric properties measurement appears as a promising method for controlling on-line the salting process in meat industry. Dielectric spectroscopy studies have been performed on raw and salted Longissimus dorsi pork samples. Dielectric spectra were measured in the frequency range from 500 MHz to 20 GHz by an Agilent 85070E open-ended coaxial probe connected to an Agilent E8362B Vector Network Analyzer immediately after salting process and also 16 h. Salt content, moisture, water activity and volume were also measured. It has been demonstrated that the dielectric properties are a good tool to analyze the share of the added sodium chloride molecules in the muscle tissue during the salting treatment (bounded and solved ions).     

Physicochemical properties of five cocoyam (Colocasia esculenta and Xanthosoma sagittifolium) starches

Physicochemical properties of starches of five cocoyam cultivars were evaluated. CIE L^*, a^*, b^* colour parameters of corm and starches were measured. Amylose, pasting and functional properties of the starches were investigated using colourimetric, Rapid Visco-Analyser and standard methods respectively. Cocoyam starches were white in colour as shown by L^* (84.83–88.65), a^* (+0.01–+1.19), and b^* (+15.33–+16.54) values. Starch granule sizes varied significantly in length (6.47–13.63 μm) and width (5.36–8.45 μm), while amylose content ranged from 11.55% (NCe002) to 33.77% (NXs001). Peak (49.09–141.96 RVU), breakdown (49.09–141.96 RVU), final (189.79–327.42 RVU) viscosities, pasting temperature (84.53–88.75 °C) and time (4.55–4.97 min) varied significantly (p < 0.05) among cultivars. Also, water absorption capacity (21–36%), pH (4.8–5.3), gelling point (60.5–69.5 °C), foam capacity (4.46–18.28%), bulk density (0.14–1.15 g/mL) and swelling power (2.31–10.09) varied significantly (p < 0.05) among the cultivars. Average yield of the starches varied significantly from 10.03 (NCe001) to 18.61% (NXs001).     

Characterization,amino acid composition and in vitro digestibility of hemp (Cannabis sativa L.) proteins

The protein constituents and thermal properties of hemp (Cannabis sativa L.) protein isolate (HPI) as well as 11S- and 7S-rich HPIs (HPI-11S and HPI-7S) were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and different scanning calorimetry (DSC), and their amino acid composition and in vitro digestibility were also evaluated, as compared to soy protein isolate (SPI). SDS-PAGE analysis showed that the edestin (consisting of acidic and basic subunits, AS and BS) was the main protein component for HPI and HPI-11S, while HPI-7S was composed of the BS of edestin and a subunit of about 4.8 kDa. DSC analysis characterized thermal transition of the edestin component and the possible present form of different subunits. Except lysine and sulfur-containing amino acids, the essential amino acids of various HPIs met the suggested requirements of FAO/WHO for 2–5 year old infants. The proportion of essential amino acids to the total amino acids (E/T) for HPI (as well as HPI-11S) was significantly higher than that of SPI. In an in vitro digestion model, various protein constituents of various HPIs were much easily digested by pepsin plus trypsin, to release oligo-peptides with molecular weight less than 10.0 kDa (under reduced condition). Only after pepsin digestion, in vitro digestibility of HPIs was comparable to that of SPI, however after pepsin plus trypsin digestion, the digestibility (88–91%) was significantly higher than that (71%) of SPI (P < 0.05). These results suggest that the protein isolates from hempseed are much more nutritional in amino acid nutrition and easily digestible than SPI, and can be utilized as a good source of protein nutrition for human consumption.     

Purification and identification of polysaccharide derived from Chlorella pyrenoidosa

The conditions for extracting and purifying polysaccharides from Chlorella pyrenoidosa, including intensity and duration of ultrasound, the temperature and incubation time, and ethanol concentration, were investigated through an orthogonal design of L₁₆(4⁵) in this work. High performance liquid chromatography (HPLC) and gas chromatography (GC) were used to characterize the compounds in C. pyrenoidosa. The highest yield of 44.8 g kg⁻¹ was achieved at 400 W of ultrasound for 800 s and then followed by incubation in water bath at 100 °C for 4 h in 80% ethanol. Two polysaccharide fractions (S1 and S2) were separated from the extracts of C. pyrenoidosa using Sepharose 4B column chromatography. The average molecular weights (M_w) of S1 and S2 were 81,877 Da and 1749 Da, respectively. Gas chromatographic (GC) traces of the hydrolyzed polysaccharides showed that most of the majority of monosaccharide in both fractions was mannose (78.0% and 76.5% of relative mass from S1 and S2, respectively) with low levels of glucose (13.2% and 8.4% of relative mass from S1 and S2, respectively). The Fourier-transform infrared spectra (FT-IR) of S1 and S2 revealed typical characteristics of polysaccharides. Both samples had the characteristics of hydroxyl groups, weak C–H band and α-pyranoses; however, only S2 had a carboxyl group.     

Characterization of bacteriocins produced by two strains of Lactobacillus plantarum isolated from Beloura and Chouriço, traditional pork products from Portugal

Bacteriocins bacST202Ch and bacST216Ch, produced by Lactobacillus plantarum strains isolated from Beloura and Chouriço, respectively, inhibited the growth of a number of Gram-positive and Gram-negative meat spoilage bacteria. According to trycine–SDS–PAGE, bacST202Ch and bacST216Ch are approximately 3.5 and 10.0 kDa in size, respectively. Maximal activity of bacST202Ch (25,600 AU/ml) was recorded after 27 h of and bacST216Ch (102,400 AU/ml) after 22 h of growth. The mode of activity, as determined against Enterococcus faecium HKLHS, is bactericidal. Both peptides adsorb to the surface of the producer cells, but at very low concentrations. Both peptides remained active after 120 min at 100 ^oC and after 2 h of incubation at pH 2.0–12.0. Treatment for 120 min at 121 ^oC did not affect bacST216Ch activity. Activity of bacST202Ch and bacST216Ch was not affected by 1% Triton X-100, Tween 80, Tween 20, SDS, NaCl, urea and EDTA. Bacteriocin ST216Ch was deactivated in the presence of 1% Triton X-114. The nucleotide sequence of a 1044 bp DNA fragment amplified from L. plantarum ST202Ch is identical to the structural gene encoding pediocin PA-1, suggesting that the two bacteriocins are identical. Based on the broad spectrum of antibacterial activity, strains ST202Ch and ST216Ch may be used as starter cultures in the fermentation of meat products.     

Seasonal variation in red deer (Cervus elaphus) venison (M. longissimus dorsi) drip loss,calpain activity,colour and tenderness

Sixty four young red deer (Cervus elaphus) stags (< 2 years old) were slaughtered at four different times (December (Group 1); n = 17, March (Group 2); n = 8, July (Group 3); n = 20 and September (Group 4); n = 19) to evaluate seasonal effects on venison quality. M. longissimus dorsi samples for calpain analysis were collected on the slaughter line and the rest of these muscles were collected at 1 day post-slaughter. Loins were divided into four parts and randomly allocated to storage for 1 day, 3, 9 or 14 weeks at −1.5 °C and then vacuum packaged. Seasonal variation was demonstrated in venison pH. Highly significant positive regressions were found for shear force (P < 0.001) and colour display life (P < 0.001) on pH, where higher pH values were associated with tougher venison and longer colour display life. A clear trend of increasing fluid loss during storage, calculated as amount of purge at 14 weeks of storage minus the amount of drip loss at 1 day post-slaughter, was evident, averaging 2.5% (SEM 0.17) over the four groups. The relative activities of the calpastatin-bound calpain, μ-calpain and m-calpain all exhibited a seasonal pattern although there was no evidence (P > 0.05) that this affected tenderness. There was a highly significant (P < 0.001) negative regression for the average over the four storage times of drip and purge on calpastatin-bound calpain activity.     

Growth and carcass fatty acid composition of beef steers fed soybean oil for increasing duration before slaughter

Duration of soybean oil (SBO) supplementation needed to enhance carcass conjugated linoleic acid (CLA) and trans-vaccenic (TVA) content was examined using 96 beef steers (293.6 ± 3.9 kg) fed a 78% corn-based diet supplemented with SBO for 0, 77, 137, or 189 days before slaughter. Duration of SBO supplementation had no effect (P ? 0.15) on animal performance or carcass traits, nor (P ? 0.15), total, total saturated, or total polyunsaturated fatty acids of Longissimus dorsi (LD). Concentrations of CLA in LD were not affected (P ? 0.18) by SBO supplementation. Concentrations of monounsaturated fatty acids (MUFA) decreased linearly (P = 0.03) in LD, whereas TVA increased (P = 0.04) in adipose tissue and tended (P = 0.07) to increase in LD with increasing duration of SBO supplementation. Supplementing SBO to a concentrate-based diet may enhance TVA without impacting CLA, while reducing the MUFA content of lean beef.     

Acidic degradation and enhanced antioxidant activities of exopolysaccharides from Cordyceps sinensis mycelial culture

An exopolysaccharide (EPS) fraction isolated from mycelial culture of a Cordyceps sinensis fungus, designated EPS-1 with an average molecular weight (MW) of 38 kDa, was hydrolysed in dilute sulphuric acid solution at pH 1 and 90 °C, yielding two major MW fractions, 3.0 kDa and 30 kDa, respectively. While the proportion of lower MW fraction increased with the hydrolysis period (18% in 0.5 h and 92% in 10 h), the polydispersity (M_w/M_n) of EPS decreased steadily (from 1.47 initially to 1.10 in 10 h). The IR spectra of hydrolysed EPS fractions showed changes only in the C–O–C and C–O–H band peaks from that of EPS-1. These results suggest that the hydrolysis of EPS in the acidic solution caused the EPS degradation mainly by cleaving the glycosidic linkage but no change in the primary molecular structure. The hydrolysed EPS fractions had much higher (30–80%) antioxidant and radical-scavenging activities.     

Novel foods with microalgal ingredients – Effect of gel setting conditions on the linear viscoelasticity of Spirulina and Haematococcus gels

Microalgae represent an alternative and innovative source of natural ingredients that can be used in the development of novel food products. Biologically active compounds (e.g. carotenoids) are naturally encapsulated within microalgal cells, being able to resist harsh technological conditions involved in food technology processes. The aim of this work was to study the effect of adding Haematococcus pluvialis and Spirulina maxima microalgal biomass on the linear viscoelastic behaviour of vegetarian food gels prepared from pea protein, κ-carrageenan and starch. The gelation process was monitored in situ through dynamic oscillatory measurements, under different thermal profile conditions. Increasing temperature (70–90 °C, 5 min) resulted in more structured gels, while the effect of time (5–30 min, at 90 °C) was less pronounced. The effect of heating and cooling rates on gel setting was also studied. Haematococcus gels were highly structured and less dependent on gel setting conditions. Spirulina gels presented lower values of viscoelastic functions than the control (gel matrix without microalgae), but this was overcome when using lower heating/cooling rates.