Microbial transglutaminase and caseinate as cold set binders: Influence of meat species and chilling storage

The effect of microbial transglutaminase/sodium caseinate (MTG/C) systems on meat batter characteristics (water binding and textural properties of raw and cooked products) was studied in the presence of NaCl (1.5 g/100 g) and sodium tripolyphosphate (0.5 g/100 g), and storage time (96 h at 3 °C) for three meat species (pork, chicken, lamb). Samples prepared from pork and lamb with only MTG/C (no salts) had the highest cooking loss (CL) values, about 23 and 29 g/100 g, respectively; for chicken, the CL was less than 13 g/100 g. Hardness (Hd) and chewiness (Cw) generally tended to be higher in cooked samples containing MTG/C than in samples containing only salts. Products combining salts and MTG/C had higher (P<0.05) Hd and Cw. The efficiency of the MTG/C system as a texture conditioner of cooked products varied with the meat source.     

Lipid and protein structure analysis of frankfurters formulated with olive oil-in-water emulsion as animal fat replacer

Lipid and protein structural characteristics of frankfurter formulated with olive oil-in-water emulsion stabilized with soy protein isolate (SPI) as pork backfat replacer were investigated using Fourier transform infrared spectroscopy (FT-IR). Proximate composition and textural properties were also evaluated. Different frankfurters were reformulated: F/PF with pork backfat, F/SPI with oil-in-water emulsion stabilized with SPI and F/SPI + SC + MTG with emulsion stabilized with a combination of SPI, sodium caseinate (SC) and microbial transglutaminase (MTG). Replacement of pork backfat with these emulsions produced an increase (P < 0.05) of hardness, springiness, cohesiveness and chewiness but a reduction (P < 0.05) of adhesiveness. F/SPI and F/SPI + SC + MTG frankfurters showed the lowest (P < 0.05) half-bandwidth in the 2922 cm⁻¹ band, which could be related to lipid chains were more ordered than in F/PF. Modifications in the amide I band profile revealed a higher concentration of aggregated intermolecular β-sheets in F/SPI + SC + MTG samples. Lipid and protein structural characteristics could be associated with specific textural properties of healthier frankfurters.     

Batter rheology and bread texture of sorghum‐based gluten‐free formulations modified with native or pregelatinised cassava starch and α‐amylase

The influence of α‐amylase (0–0.3 U g^?1) on the crumb properties of gluten‐free sorghum batter and bread, respectively, was investigated. The formulations were modified using native or pregelatinised cassava starch (i.e. batter A – 17% pregelatinised starch, 83% sorghum, 100% water fwb; batter B – 17% native starch, 83% sorghum, 100% water fwb; and batter C – 30% native starch, 70% sorghum, 80% water fwb). The batters had solid viscoelastic character with the storage modulus predominant over the loss modulus. Storage moduli of batter A decreased with increasing angular frequency, whereas the moduli of batters B and C were independent from the angular frequency. Increasing enzyme concentration did not affect the loss factors of the batters. Batters’ resistance to deformation, from highest to lowest, followed the order C > A > B. Increasing enzyme concentration decreased crumb firmness, cohesiveness, springiness, resilience and chewiness but increased adhesiveness. Overall, breads containing native starch had better crumb properties (i.e. springier and less firm, chewy and adhesive) than breads containing pregelatinised starch.     

Oil bulking agents based on polysaccharide gels in meat batters: A Raman spectroscopic study

A Raman spectroscopic study was performed to determine protein and lipid structural properties in meat batter containing oil bulking agents as pork backfat replacers. Meat batters were prepared with pork backfat (MB-PF) or with a combination of olive oil, sodium alginate, CaSO₄, sodium pyrophosphate and dextrin (MB-A/D) or inulin (MB-A/I) as a fat replacer. Proximate composition, pH, cooking loss (CL), colour and texture were evaluated. MB-A/D and MB-A/I both showed lower (P < 0.05) CL and a^∗ values, higher (P < 0.05) L^∗ and b^∗ values, and higher (P < 0.05) hardness and chewiness. MB-A/I showed the highest hardness and chewiness. Enhancement of the β-sheet structure was observed in MB-A/D and MB-A/I, more so in MB-A/I. There was increased disorder in the oil acyl chains, which involve lipid–protein interactions, in both MB-A/D and MB-A/I. Structural characteristics in proteins and lipids may be associated with specific water and fat binding properties and textural characteristics of meat batters.     

Effect of bamboo salt on the physicochemical properties of meat emulsion systems

This study was conducted to determine the effects of various bamboo salts on meat batter. To accomplish this, three different batters were prepared and compared: CON, which was prepared with NaCl, BS-2, which was prepared with bamboo salt that was baked twice, BS-9, which was prepared with bamboo salt that was baked nine times. The pH of both the uncooked and cooked BS-2 and BS-9 was higher than that of the CON (P < 0.05). The emulsion stability, cooking yield, water holding capacity (WHC) and apparent viscosity of BS-2 and BS-9 were higher than those of CON. The correlation coefficient between the viscosity value and WHC was high and positive (R² = 0.672). The hardness of all treatments was significantly increased with increased cooking temperature (P < 0.05). The hardness, gumminess and chewiness of CON were higher than that of BS-9 and BS-2. The overall acceptability score between CON and BS-9 was significantly different (P < 0.05). The bamboo salts effectively improved the physicochemical properties of the meat batter.     

Response surface methodology study on the effects of salt,microbial transglutaminase and heating temperature on pork batter gel properties

Response surface methodology was used to investigate the main effects and interactions of sodium chloride (0–2%), microbial transglutaminase preparate (MTG, 0–0.6%) and heating temperature (HT, 70–100°C) on water binding, textural and colour characteristics of pork batter gels cooked to an internal temperature of 70 °C. Lower salt gels showed decreases in hardness, chewiness and elastic properties, as well as significant reduction in the cooking yield and increase of expressible moisture. Salt levels also affected gel colour parameters, with Hunterlab a* and b* values being inversely correlated with salt concentration. MTG addition favourably reduced the cooking loss and increased hardness and chewiness of gels, but was not able to improve these parameters in low-salt products to the same levels as the high-salt products. Heating temperature was found to have relatively minor effect, primarily through its interaction with salt level and in a quadratic term affecting the elasticity and springiness of the gels.     

Decreased gelling and emulsifying properties of myofibrillar protein from repeatedly frozen-thawed porcine longissimus muscle are due to protein denaturation and susceptibility to aggregation

The effects of freeze–thaw cycles (FT, 0, 1, 3 and 5 times) on protein functional properties of porcine longissimus muscle were investigated. FT increased gapping between muscle fibres and tore muscle fiber bundles. Myofibrillar protein (MP) isolated from FT muscle showed an increased hydrophobicity (P < 0.05), reduced thermal transition temperatures (T_max) and enthalpy of denaturation (ΔH) (P < 0.05), and enhanced susceptibility to thermal aggregation. These structural changes resulted in major losses in protein functionalities, e.g., 41–43% reductions (P < 0.05) in MP emulsifying capacity and emulsion stability after five FT cycles. The ability of MP to form a viscoelastic gel network, as analyzed by small-strain oscillatory rheological testing, also attenuated with FT cycles. The FT process lowered (P < 0.05) water-holding capacity (WHC), whiteness, and texture (hardness, springiness, chewiness and cohesiveness) of MP gels. Overall, repeated FT had a detrimental effect on the general functionality of porcine MP, and protein denaturation and aggregation were implicated in the functionality losses.     

Emulsifying properties of sweet potato protein: Effect of protein concentration and oil volume fraction

The effect of protein concentrations (0.1, 0.25, 0.5, 1.0, 1.5 and 2.0% w/v) and oil volume fractions (5, 15, 25, 35 and 45% v/v) on properties of stabilized emulsions of sweet potato proteins (SPPs) were investigated by use of the emulsifying activity index (EAI), emulsifying stability index (ESI), droplet size, rheological properties, interfacial properties and optical microscopy measurements at neutral pH. The protein concentration or oil volume fraction significantly affected droplet size, interfacial protein concentration, emulsion apparent viscosity, EAI and ESI. Increasing of protein concentration greatly decreased droplet size, EAI and apparent viscosity of SPP emulsions; however, there was a pronounced increase in ESI and interfacial protein concentration (P < 0.05). In contrast, increasing of oil volume fraction greatly increased droplet size, EAI and emulsion apparent viscosity of SPP emulsions, but decreased ESI and interfacial protein concentration significantly (P < 0.05). The rheological curve suggested that SPP emulsions were shear-thinning non-Newtonian fluids. Optical microscopy clearly demonstrated that droplet aggregates were formed at a lower protein concentration of <0.5% (w/v) due to low interfacial protein concentration, while at higher oil volume fractions of >25% (v/v) there was obvious coalescence. In addition, the main components of adsorbed SPP at the oil–water interface were Sporamin A, Sporamin B and some high-molecular-weight aggregates formed by disulfide linkage.     

A model approach to starch and protein functionality in a pound cake system

Different modified wheat starches were used in a model pound cake recipe. The properties of the starches were linked to differences in batter viscosity, cake height and protein extractability during baking, collapse during cooling and final cake quality. The impact of incorporation of 30% cross-linked (CL) starches on batter properties during baking was much smaller than that of incorporation of the same level of hydroxypropylated (HP) starches. Incorporation of HP starches with various degrees of modification in the recipe caused batter viscosity during baking to start rising from 92 or 88 °C rather than at 96 °C and diminished oven rise significantly. Furthermore, the extractability of the protein in cakes containing HP starch was significantly higher. During cooling, control cake collapsed less than did CL starch-containing cake, which itself collapsed significantly less than did HP starch-containing cake. Presumably, most of the cake collapse takes place before the starch gel is formed during cooling. Protein and starch apparently function in determining cake quality, by providing the cell walls with structural material and high resistance to collapse. Starch does not prevent cake collapse, but still co-determines crumb structure, whereas a strong correlation was found between the gel-forming capacity of starch blends and intrinsic crumb firmness (r = 0.99). Furthermore, a strong negative correlation was found between springiness and percentage of extractable protein in final cakes (r = −0.95). We conclude that the combination of a protein network, formed during baking, with a starch gel, formed during cooling, makes up the crumb cell walls and determines cake quality.     

Effects of dry,vacuum, and special bag aging; USDA quality grade; and end-point temperature on yields and eating quality of beef Longissimus lumborum steaks

This study evaluated the effects of three aging methods: (dry (D), wet (W), and special bag (SB)); two quality grades [USDA Choice((≥ Small⁵⁰ marbling) and Select); and two cooked end-point temperatures (62.8 °C and 71.1 °C) on physico-chemical traits of instrumental tenderness, color, and sensory properties of Longissimus lumborum beef muscle. Dry-aged loins had higher (P < 0.0001) weight loss than W or SB aged loins. However, D and SB aged loins had similar (P > 0.05) combined losses. W aged loins had higher (P < 0.01) L* values than D or SB aged loins. Warner–Bratzler shear force of steaks was not affected (P > 0.05) by aging method or quality grade but increased (P < 0.0001) as end-point temperature increased. Sensory panel evaluation also showed no effect (P > 0.05) of aging method or quality grade on myofibrillar tenderness, juiciness, connective tissue amount, overall tenderness or off flavor intensity. Steaks cooked to 62.8 °C were juicier (P < 0.05) than those cooked to 71.1 °C. Neither D nor SB aging had advantages over W aging.     

Effects of live weight and processing on the sensory traits,androstenedione concentration and 5-alpha-androst-16-en-3-one (androstenone) concentration in boar meat

Twenty-nine crossbred boars were used to evaluate the effects of live weight and processing on the sensory attributes and concentrations of androstenedione and androstenone (boar taint) in boar meat. Boars were stratified by litter across six weight group endpoints (90.9, 95.5, 100.0, 104.5, 109.1, and 113.6 kg). Back fat and longissimus muscle from the lumbar region were used for androstenone determination, proximate analysis and sensory evaluation. Hams were cured for sensory analysis and were used to determine androstenone concentrations. Androstenone as an off-flavor did not differ (P > 0.05) among treatments for longissimus lean or cured hams and was found to be in the “threshold” to “none detected” range. Back fat androstenone concentration was positively correlated (P < 0.05) to hot carcass weight, however, lean androstenone concentration was not (P > 0.05). No relationship was found (P > 0.05) between androstenone concentration and days on feed, average daily gain or androstenedione concentration. Additionally, further processing decreased androstenone concentration by approximately 29%.     

Quality Indicators of Rice-Based Gluten-Free Bread-Like Products: Relationships Between Dough Rheology and Quality Characteristics

The design of gluten-free bread-like products involves the study of gluten-free dough rheology and the resulting baked product characteristics, but little information has been obtained connecting dough and baked product properties. The aim of this study was to determine quality predictors of gluten-free bread-like products at dough level by defining possible correlations between dough rheological properties and both instrumental parameters and sensory characteristics of those products. Diverse rice-based gluten-free doughs were defined and rheologically characterised at dough level, and the technological and sensorial quality of the resulting baked products was investigated. Dough Mixolab® parameters, bread-like quality parameters (moisture content, specific volume, water activity, colour and crumb texture) and chemical composition significantly (P?<?0.05) discriminated between the samples tested. In general, the highest correlation coefficients (r?>?0.70) were found when quality instrumental parameters of the baked products were correlated with the dough Mixolab® parameters, and lower correlation coefficients (r?<?0.70) were found when sensory characteristics were correlated with dough rheology or instrumental parameters. Dough consistency during mixing (C1), amplitude and dough consistency after cooling (C5) would be useful predictors of crumb hardness; and C5 would be also a predictor of perceived hardness of gluten-free bread-like products.     

Chemical and biochemical changes of hybrid catfish fillet stored at 4 °C and its gel properties

Chemical and biochemical changes of aquacultured hybrid catfish fillet (Clarias macrocephalus × Clarias gariepinus) and its gel-forming ability as affected by age and sex of fish along with storage time were investigated. Fillets were stored at 4 °C for 0, 3, 6, 9, 12 and 15 days. There was no significant effect of sex and age of fish as well as storage time on fat, moisture and ash contents (P > 0.05). The total protein, water soluble protein, and salt soluble protein contents of the fillets significantly decreased with storage time (P < 0.05). On the other hand, pH, total volatile base nitrogen (TVB-N) and autolytic degradation products (ADP) increased as storage time continued (P < 0.05). Decreases in Ca²⁺-ATPase activity and gel properties were observed as storage time increased. However, there was no significant effect of either sex or age of fish on textural properties of gel (P > 0.05). Hybrid catfish fillet stored at 4 °C should be processed within 6 days.     

Antioxidant effects of soy sauce on color stability and lipid oxidation of raw beef patties during cold storage

This study was conducted to evaluate the antioxidant effects of soy sauce on lipid oxidation and color stability of raw beef patties. Raw beef patties were formulated with four solutions such as NaCl (sodium chloride solution), NaCl/SS (1:1 ratio of sodium chloride and soy sauce solution), SS (soy sauce solution), or SS/A (soy sauce solution combined with 0.05% ascorbic acid) in the same salt concentration. Addition of soy sauce resulted in the decreased pH, lightness, and increased yellowness. Treatment SS/A had the lowest percent of metmyoglobin during storage (P < 0.05). A reduction (P < 0.05) in the 2-thiobarbituric acid, peroxide, and conjugated diene concentration as result of soy sauce addition were observed in treatments SS and SS/A at the end of the storage period. There were no differences (P > 0.05) in free fatty acid concentration at the end of storage. The combined addition of soy sauce and ascorbic acid greatly improved (P < 0.05) color stability and retarded lipid oxidation.     

Effects of purified monoglycerides on Canadian short process and sponge and dough mixing properties,bread quality and crumb firmness during storage

The effects of increasing levels of a wide range of purified saturated (C12:0–C22:0) and unsaturated (C18:1 cis, C18:1 trans, C18:2, C18:3) monoglycerides on Canadian short process (CSP) and sponge and dough (SDP) mixing properties, bread quality and crumb firmness during storage have been studied. For both processes, higher levels (0.5–1.0%) of polyunsaturated monoglycerides (C18:2, C18:3) caused the largest significant (p < 0.05) increases in mixing time and mixing energy requirements while shorter chain saturated monoglycerides (C12:0, C14:0) significantly increased mixing time and energy requirements for the CSP. Most monoglycerides had positive effects on CSP loaf volume and bread score while no improvement was evident for the SDP. For both processes, crumb firmness during storage was significantly reduced by addition of C16:0 and C18:0 saturated and cis- and trans- monounsaturated monoglycerides and was significantly increased by addition of C12:0 and the polyunsaturated monoglycerides. Changes in crumb firmness during storage were attributed to the effects of monoglycerides on both initial crumb firmness and the rate of crumb firming. The baking process appeared to have a strong influence on the relative impact of monoglycerides on overall crumb firmness and, in particular, initial firmness.     

Beef quality attributes as affected by increasing the intramuscular levels of vitamin E and omega-3 fatty acids

In order to investigate the effects of increasing beef n-3 fatty acid content and the protective effects of vitamin E antioxidant activity on meat quality characteristics, 80 feedlot steers were fed 4 different diets (control, high vitamin E, 10% ground flaxseed or high vitamin E-10% ground flaxseed). While dietary treatments had no effect (P > 0.05) on meat composition or tenderness values, the increase in oxidation products was lower (P = 0.046) in meat from vitamin E supplemented steers and higher (P = 0.006) in meat from flaxseed fed animals. The increase in α-tocopherol tissue levels (P < 0.001) in meat from animals fed flaxseed and increased dietary vitamin E resulted in the lowest drip loss values (P = 0.013). As expected, display time had a large effect on retail traits in both steaks and patties (P < 0.001). While retail traits of steaks were not affected by the dietary treatments (P > 0.05), feeding flaxseed decreased (P < 0.05) ground beef retail scores, which were not corrected by higher levels of dietary vitamin E. Finally, although no effect (P > 0.05) was observed among treatments for sensory attributes in steaks, the correlations of a combined n-3:α-tocopherol ratio against retail and sensory attributes (P < 0.05) suggest that increased n-3 fatty acids levels require increased dietary antioxidants, such as vitamin E to avoid negative effects on meat quality from a loss in oxidative stability.     

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).     

Low-fat frankfurters enriched with n−3 PUFA and edible seaweed: Effects of olive oil and chilled storage on physicochemical,sensory and microbial characteristics

This article reports a study of the physicochemical, sensory and microbiological characteristics of low-fat (10%) and n−3 PUFA-enriched frankfurters as affected by addition of seaweed (5% Himanthalia elongata), partial substitution (50%) of animal fat by olive oil and chilled storage (41 days at 2 °C). The presence of seaweed improved water and fat binding properties, reduced (P < 0.05) lightness and redness and increased (P < 0.05) the hardness and chewiness of low-fat frankfurters enriched with n−3 PUFA. The effect of olive oil on those characteristics was less pronounced than that of seaweed. Replacing pork backfat with olive oil in frankfurters produced acceptable sensory characteristics, similar to control, while addition of seaweed resulted in less acceptable products, due mainly to the special flavour of the seaweed. Formulation and storage time affected the total viable count and lactic acid bacteria count. Frankfurters containing olive oil and seaweed had the highest total viable count from day 14 of storage, with lactic acid bacteria becoming the predominant microflora.     

Gelation properties of salt-extracted pea protein isolate catalyzed by microbial transglutaminase cross-linking

Gelation is a fundamental functional characteristic of plant proteins. In this paper, a salt-extracted pea protein isolate (PPI) was mixed with microbial transglutaminase (MTG) to produce gels and the gelation properties were studied. When the MTG level increased, the magnitude of both the G′ and G″ moduli also increased, which means the gel strength increased. A second order polynomial equation was used to describe the relationships between the G′, G″ modulus and TG level. It was found that with increased heating and cooling rate at the same MTG level, G′ and G″ tended to decrease, resulting in a weaker gel. This was attributed to the rearrangement time of pea protein molecules; slower heating and cooling rates enabled protein molecules to have more time to rearrange and therefore form a stronger gel. At the same MTG level, higher pea protein concentration resulted in higher G′ and G″ values and a power law relationship was found between G′ and pea protein concentration or G″ and pea protein concentration. Frequency sweep data of PPI show that the MTG treatment resulted in higher G′ values and lower tan delta values, indicative of a stronger more elastic gel. The minimum gelation concentration was found to be 3% (w/v) with 10 U MTG treatment, lower than 5.5% required when no MTG was present. When compared to PPI and soy protein isolate (SPI) with and without 10 U MTG treatment, the gel strength of PPI with MTG was stronger than that of SPI with MTG treatment, whereas the opposite was true without the MTG treatment. SDS-PAGE showed that at the same pea protein concentration, higher MTG level induced more cross-linking as fainter bands were seen on the gel and there was a shift in the relative intensities of the bands in the molecular weight range of 35–100 kDa.     

Effect of some operating variables on the microstructure and physical properties of a novel Kefir formulation

In this work, the rheological and textural properties, water-holding capacity (WHC), syneresis, and microstructure of a novel formulation of Kefir were studied by varying the incubation time and temperature, as well as the ratio of peanut-milk and skimmed-milk. Generally, all the experimental responses resulted to be significantly affected (p < 0.05) by all dependent variables examined. Kefir WHC was not significantly influenced (p > 0.05) by the fermentation temperature.