The effect of oxygen level and exogenous α-tocopherol on the oxidative stability of minced beef in modified atmosphere packs

The effect of oxygen level (20, 40, 60 and 80%) in modified atmospheres on the oxymyoglobin content of intact and minced beef (M. semimembranosus, SM) was evaluated. There was no significant difference in the oxymyoglobin content of minced SM stored for up to 4 days in modified atmosphere packs containing 20, 40, 60 or 80% O(2). After 7 days, oxymyoglobin in minced SM decreased significantly (P?0.05) with decreasing oxygen level but by day 10 all samples had similarly low oxymyoglobin contents. Lipid oxidation increased significantly (P?0.05) between day 7 and 10 of storage in minced SM stored in modified atmospheres containing 40, 60 or 80% O(2). Oxymyoglobin and lipid oxidation occurred in intact SM but the extent of oxidation was lower than for minced SM. Exogenous α-tocopherol, dispersed in olive oil and added to minced SM (300 and 3000 mg α-tocopherol/kg lipid), had no significant effect on Hunter 'a' values when the samples were stored in low (20%) or high (80%) oxygen atmospheres. Exogenous α-tocopherol addition led to a significant reduction in lipid oxidation (P?0.05) in minced SM stored in high but not in low oxygen atmospheres.     

Protective effect of tetrahydrocurcumin and chlorogenic acid against streptozotocin–nicotinamide generated oxidative stress induced diabetes

The present study was undertaken to investigate the protective effect of tetrahydrocurcumin (THC) and chlorogenic acid (CGA) against streptozotocin (STZ)–nicotinamide (NA)-induced type 2 diabetes in adult Wistar rats. Diabetes was induced in experimental rats weighing 180–220 g, by a single intraperitoneal (i.p.) injection of STZ (45 mg/kg BW), 15 min after the (i.p.) administration of NA (110 mg/kg BW). THC (80 mg/kg BW) and CGA (5 mg/kg BW) were orally administered to diabetic rats for a period of 45 days. Fasting plasma glucose, glycosylated haemoglobin (HbA_1C), thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides (LOOH) were significantly increased, whereas insulin, total haemoglobin (Hb), non-enzymic antioxidants (reduced glutathione (GSH), vitamin C, vitamin E and ceruloplasmin) were decreased significantly in diabetic rats. Though the diabetic rats treated with THC and CGA individual exerts beneficial effects in all the biochemical parameters in (STZ)-induced diabetic rats. The combined treatment with THC and CGA normalized all the above-mentioned biochemical parameters in STZ-induced diabetic rats. Normal pancreatic histological architecture in THC and CGA treated diabetic rats revealed that these phytochemical exert higher degree of protection when administered in combination than single treatment of individual compounds.     

The effect of glycation on foam and structural properties of β-lactoglobulin

The goal of the present work was to evaluate whether the Maillard reaction, with glucose and lactose as substrates, improves the foaming properties of β-lactoglobulin. Lactose led to the lowest degree of modification without significant differences by reaction time and by protein:sugar molar ratio. However, in the case of glucose, the degree of glycation increases with reaction time and molar ratio. The results obtained by UV fluorescence, surface hydrophobicity and differential scanning calorimetry clearly showed differences in the degree of folding of β-lactoglobulin upon modification with different sugars or thermal treatment, with changes in the foaming capacity of β-lactoglobulin. All the modified samples exhibited a significant increase (α ? 0.05) in draining stability (Kg) as compared to the non-thermally treated sample. In addition, foams formed by lactose-glycated samples were more stable than those formed by glucose-glycated ones. A significant increase (α ? 0.05) of foam stability with reaction time was also detected, particularly in glucose-glycated samples.     

The effect of climate variations on glulam—an experimental study

Climate variations affect timber structures by causing moisture induced stresses which may lead to cracks in timber members. The paper presents experimentally determined moisture induced stresses that arise perpendicular to the grain of glulam specimens during exposure to 1-dimensional drying and wetting. Although to a certain extent reduced by creep effects, the determined tensile stresses can significantly exceed the characteristic tensile strength of glulam. Additional measurements of moduli of elasticity (E) and hygroexpansion coefficients (α) revealed that these parameters are strongly affected by the geometrical configuration (pith locations) of the specimens. By means of all the parameters determined here, it can be avoided that parameters have to be selected from different literature sources, which introduces large uncertainties into the numerical simulations.     

Synergistic effect of 3,4-dihydroxyphenylglycol with hydroxytyrosol and α-tocopherol on the Rancimat oxidative stability of vegetable oils

The current work evaluated the ability of pure 3,4-dihydroxyphenylglycol (DHPG) and hydroxytyrosol (HT) in combination with a commercial phenolic extract from Olea europaea rich in HT to prevent the oxidation of edible vegetable oils. The commercial phenolic extract was highly soluble in all matrices and significantly improved the oxidation stability and delayed the onset of rancidity of oils compared to a control (with no antioxidant). The combinations of DHPG with other natural antioxidants, such as HT and α-tocopherol, showed that it can be a useful supplement to increase the shelf life of sunflower oil. Synergism was observed when DHPG and HT were added in combination. The synergistic effect was directly related to the concentration ratio between both antioxidants. The mixtures containing DHPG/α-tocopherol and DHPG/HT/α-tocopherol also showed effectiveness in delaying oxidation.     

Hepatoprotective effect of peptic hydrolysate from salmon pectoral fin protein byproducts on ethanol-induced oxidative stress in Sprague–Dawley rats

Bioactive peptides were generated by pepsin hydrolysis from salmon pectoral fin protein byproduct, and the hepatoprotective effect of the peptic hydrolysate (PH) on ethanol-induced oxidative stress was investigated in Sprague–Dawley rats. Administration of ethanol for 4 weeks significantly (p < 0.05) increased serum markers of liver damage, such as alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase; however, these activities decreased significantly (p < 0.05) after PH administration. Elevated thiobarbituric acid reactive substance levels in liver tissue and serum decreased significantly (p < 0.05) following administration of PH. Ethanol exposure significantly (p < 0.05) decreased glutathione contents in liver and serum, and hepatic antioxidant enzyme activities such as superoxide dismutase and glutathione peroxidase, while the PH treatment significantly (p < 0.05) increased these altered parameters. These results indicate that the PH had a protective effect against ethanol-induced hepatotoxicity that was comparable to that of silymarin, which was supported by evaluating liver histopathology in the rats.     

Migration of α-tocopherol from LDPE films to corn oil and its effect on the oxidative stability

The migration of α-tocopherol (α-T) from low density polyethylene (LDPE) films, added with 20 (film A) and 40 mg g^?1 (film B) to corn oil for 12 weeks at 5, 20 and 30 °C was determined. A LDPE film added with no α-T was used as control (film C). Diffusion coefficient (D) values for the film A system were 1.4 × 10^?11, 7.1 × 10^?11 and 30.3 × 10^?11 cm² s^?1 at 5, 20 and 30 °C, respectively. Meanwhile, D values for the film B system were 1.3 × 10^?11, 9.6 × 10^?11 and 51.1 × 10^?11 cm² s^?1 at the same temperatures. The activation energy (E_a) for the diffusion of α-T was 126.5 (film A) and 105.9 kJ mol^?1 (film B). The effect of the migration of α-T on the oxidative stability of corn oil was evaluated by monitoring hexanal content by solid phase micro-extraction (SPME) and gas chromatography. The hexanal content in the oil showed that both films added with α-T resulted suitable to maintain the oxidative stability of the oil for about 16 weeks at 30 °C, compared to 12 weeks for the oil in contact with the film C.     

The effect of agitation on the nucleation of α-lactose monohydrate

Nucleation in an industrial crystallisation process determines how many crystals are formed and defines the final particle size distribution. This parameter plays a critical role in determining the success of an industrial lactose crystallisation, impacting yield, throughput and product quality. Previous studies on lactose crystallisation have reported that mixing can influence the nucleation kinetics of α-lactose monohydrate. This work looked to authenticate this by measuring the induction time required for nucleation of supersaturated lactose solutions across a range of agitation rates. Increasing agitation increased the rate of nucleation at a given supersaturation. The results show that this is a result of an increase in the frequency of activated molecular collisions and not a change in the critical nucleus size, which remains constant at a defined supersaturation.     

The effect of different cooking procedures on microbiological and chemical quality characteristics of Tekirdağ meatballs

In this research, the effects of different cooking processes (grilling, oven, and microwave cooking) on microbial flora and chemical composition of the raw and cooked meatballs as consumed in Tekirda? were investigated. Microbial flora of the raw meatballs was as follows: total bacteria, 6.02 x 10(6) cfu/g; psychrophilic bacteria, 1.3 x 10(5) cfu/g; yeast and mould, 2.4 x 10(5) cfu/g; coliforms, 1.1 x 10(5) cfu/g; Escherichia coli, 1.0 x 10(2) cfu/g; total staphylococcae, 3.3 x 10(2) cfu/g; Staphylococcus aureus, 85 cfu/g. While Salmonella was found in only one sample, none of the samples contained Clostridium perfringens. The cooking processes clearly decreased the microbial flora (2-3 log cycles in grilling (71 degrees C) and oven-cooked (79 degrees C), 3-4 log cycles in microwave (97 degrees C) heating) of the meatballs. However, because of the crust formation and high moisture losses from the meatball surface in microwave heating, some sensorial defects were observed in the final product. Also, fat and moisture losses were higher in microwave cooking compared to the other cooking processes. In conclusion, it is advised to use slightly higher temperatures than used in the grilling or conventinal cooking procedures to increase microbial quality of the meatballs studied in this research.     

The effect of freeze–thaw cycles on microstructure and physicochemical properties of four starch gels

The effect of repeated freeze–thaw (FT) cycles (up to seven) on microstructure, thermal and textural properties of four starch gels from various botanical origins (gingko, Chinese water chestnut, potato and rice) was investigated and compared by scanning electronic microscope, differential scanning calorimetry and texture analyzer. The chemical composition and molecular structure of four starches were also examined. The Chinese water chestnut, potato and rice starch gels formed a honey-comb structure after 7 FT cycles, while gingko starch gel exhibited lamellar structure. The 7 FT cycles decreased the transition temperatures and enthalpies of four starches in comparison with each native starch, and the retrogradation percentage followed the order: rice > gingko > Chinese water chestnut > potato. The 7 FT cycles increased the hardness of all the evaluated starch gels and decreased springiness and cohesiveness. Results showed that the molecular structure of starches caused notable differences to the microstructure and textural properties of starch gels. The higher amount of longer branch chain (degree of polymerization (DP) > 18) might benefit the formation of the lamellar structure of gingko starch. The percentage of branch chains (DP 18–23) was negatively related with the springiness and cohesiveness of native starch gels, while the percentage of medium chains (DP 12–17) was positively related to the springiness of starch gels after 7 FT cycles.     

The congruence effect of food shape and name typeface on consumers’ food preferences

Both food image and name are important in advertising and packaging, which means that identifying their effects on consumer preferences is of both conceptual and managerial importance. However, although an increasing body of research currently focuses on the impact of food attributes on consumers, whether the sensory correspondences between food shape and name typeface affect consumer reactions is an under-researched topic. This paper thus comprises five studies to demonstrate the congruence effect between food shape and name typeface, whereby consumers prefer foods with a round (angular) shape that are labeled with a round (angular) name typeface. This shape–typeface congruence effect is driven by the psychological mechanism of processing fluency, which derives from the sensory correspondences between food shape and name typeface. Finally, this study identifies an important boundary condition of the congruence effect, confirming it affects only the consumer response to hedonic and not utilitarian goods. Using multiple foods and typefaces, the findings provide significant implications for processing fluency, sensory correspondences, and food marketing.     

The effect of sterilizing doses of γ-irradiation on the molecular weight and emulsification properties of gum arabic

Experiments were performed on raw, kibbled and spray-dried gum arabic. Microbiological tests showed that following a radiation dose of 10 kGy the contaminating micro-organisms were effectively inactivated. The average molecular weight of kibbled and spray dried gum arabic was shown by viscosity measurements to be somewhat reduced as the result of γ-irradiation. No significant radiation-induced changes in the molecular weight of raw gum arabic could be detected. The yields of radiolytically produced strand breaks (breaks/100 eV of radiation absorbed) have been calculated for spray-dried [G(strand breaks) = 4.1 × 10⁻¹] and for kibbled [G(strand breaks) = 2.9 × 10⁻¹]. Gel permeation chromatography confirmed this order of radiation stability and indicated that gum arabic consists of at least three major components, the larger molecular weight fraction appearing to be the more radiation sensitive. There was no measurable change in the total hexuronic acid content (20%) of any of the samples on γ-irradiation. Finally, measurements showed no adverse effect of γ-irradiation, even up to doses of 30 kGy, on the ability of the gum arabic to stabilize emulsions. The extent of chemical change induced by irradiation with sterilizing doses has no practical adverse significance and demonstrates that this technique is suitable for processing raw gum arabic samples.     

The effect of pectin concentration and degree of methyl-esterification on the in vitro bioaccessibility of β-carotene-enriched emulsions

Soluble fibers, like pectin, are known to influence the physicochemical processes during the digestion of dietary fat and may therefore affect the absorption of lipophilic micronutrients such as carotenoids. The objective of the current work was to investigate whether the pectin concentration and degree of methyl-esterification (DM) influence the bioaccessibility of carotenoids loaded in the oil phase of oil-in-water emulsions. The in vitro β-carotene bioaccessibility was determined for different oil-in-water emulsions in which 1 or 2% citrus pectin with a DM of 99%, 66% and 14% was present. Results show that pectin concentration and DM influence the initial emulsion properties. The most stable emulsions with the smallest oil droplets (D(v,0.9) of 15–16 μm) were obtained when medium or high methyl-esterified pectin was present in a 2% concentration while gel-like pectin structures (D(v,0.9) of 114 μm), entrapping oil droplets, were observed in the case where low methyl-esterified pectin was present in the aqueous emulsion phase. During in vitro stomach digestion, these gel-like structures, entrapping β-carotene loaded oil droplets, significantly enlarged (D(v,0.9) of 738 μm), whereas the emulsion structure could be preserved when the medium or high methyl-esterified pectin was present. Initial emulsion viscosity differences, due to pectin concentration and especially due to pectin DM, largely disappeared during in vitro digestion, but were still significant after the stomach digestion phase. The observed differences in emulsion structure before and during in vitro digestion only resulted in a significant difference between emulsions containing low methyl-esterified pectin (β-carotene bioaccessibility of 33–37%) and medium/high methyl-esterified pectin (β-carotene bioaccessibility of 56–62%).     

The effect of temperature on the activity of μ- and m-calpain and calpastatin during post-mortem storage of porcine longissimus muscle

The experiment was conducted to determine the effect of temperature during post-mortem muscle storage on the activity of the calpain system, the myofibril fragmentation and the free calcium concentration. Porcine longissimus muscle were incubated from 2h post-mortem at temperatures of 2, 15, 25 and 30 °C and sampling times were at 2, 6, 24, 48 and 120 h post-mortem. After 120 h at 30 °C the free calcium concentration increased to 530 μM from 440 μM at 2 °C. Incubation at temperatures higher than 2 °C resulted in the appearance of autolyzed m-calpain activity and a decrease of native m-calpain activity. Native m-calpain decreased more slowly than native μ-calpain, and the autolysis process started later. Myofibril fragmentation increased with storage time and incubation temperature, while calpastatin activity decreased. The study showed that high temperature incubation not only rapidly activated μ-calpain but at higher temperatures and later time points also m-calpain.     

Neuroprotective activity of macroalgal fucofuroeckols against amyloid β peptide-induced cell death and oxidative stress

Phlorotannins are polyphenolic compounds predominantly found in brown seaweeds tentatively identified as having neuroprotective bioactivity; however, the effects of individual constituent phlorotannins against amyloid β neurotoxicity, the main hallmark neurotoxic protein in Alzheimer’s disease (AD), is yet to be fully characterised. In this study, four phlorotannins, namely eckol, dieckol, phlorofucofuroeckol-A (PFFA) and 974-A sourced from the brown seaweed Ecklonia species were assessed for their ability to protect against the toxic effects of H₂O₂, lipid peroxidation via tert-butyl hydroperoxide (t-BHP) and Aβ_1–42 in neuronal PC12 cells. All compounds significantly scavenged reactive oxygen species (ROS). However, only PFFA and 974-A protected PC12 cells from oxidative stress-evoked neurotoxicity, providing significant increases in cell viability in response to both cytosolic (H₂O₂₎ and lipid peroxidation-evoked (t-BHP) cell stress. None of the phlorotannins tested inhibited Aβ_1–42 aggregate morphology, which suggested that their neuroprotective activity was unrelated to direct interactions with Aβ_1–42 protein. Our results indicate that while all phlorotannins tested exhibited ROS scavenging activity, only fucofuroeckol-type phlorotannins such as PFFA and 974-A afforded broader neuroprotective activity in response to both oxidative stress and amyloid β exposure. The additional amyloid-protective capacity of fucofuroeckols reveals the potential importance of the benzofuran moiety in neuroprotection and further studies are encouraged to investigate the chemico-biological basis of this distinction in the search for neuroprotective therapies in dementia and other neurodegenerative conditions.     

The combined effect of front-of-pack nutrition labels and health claims on consumers’ evaluation of food products

The majority of studies examining the effect of nutrition information on food packets (such as the nutrition information panel (NIP), front-of-pack labels (FoPLs) and health claims) have examined each in isolation, even though they often occur together. This study investigated the relationship between FoPLs and health claims since (i) they both appear on the front of packs and typically receive more attention from consumers than the NIP, (ii) they can convey contradictory messages (i.e., health claims provide information on nutrients that are beneficial to health while FoPLs provide information on nutrients associated with increased health risks) and (iii) there is currently scant research on how consumers trade off between these two sources of information. Ten focus groups (n = 85) explored adults’ and children’s reactions when presented with both a FoPL (the Daily Intake Guide, Multiple Traffic Lights, or the Health Star Rating) and a health claim (nutrient content, general-level-, or high-level). A particular focus was participants’ processing of discrepant information. Participants reported that health claims were more likely to be considered during product evaluations if they were perceived to be trustworthy, relevant and informative. Trust and ease of interpretation were most important for FoPLs, which were more likely than health claims to meet criteria and be considered during product evaluation (especially the Health Star Rating and Multiple Traffic Lights). Results indicate that consumers generally find FoPLs more useful than health claims.     

Influence of dietary β-alanine and histidine on the oxidative stability of pork

Carnosine (β-alanine-L-histidine) and anserine (β-alanine-1-methyl histidine) are endogenous antioxidants found in skeletal muscle. The objective of this research was to determine if supplementation of swine diets with histidine (histidine; 0.40%) and/or β-alanine (β-alanine; 0.225%) was an effective method to increase carnosine and anserine concentrations and the oxidative stability of Longissimus dorsi (LD) and Vastus intermedius (VI) muscles. Dietary treatments had no effect on carnosine and anserine concentrations in LD; however, histidine + β-alanine supplementation increased carnosine and anserine in VI muscle compared to β-alanine supplementation. Dietary supplementation had no effect on the formation of thiobarbituric acid reactive (TBARS) or lipid peroxides in cooked VI and LD. In salted VI and LD muscle, differences in TBARS and peroxides were observed; however, these differences did not consistently correlate with differences in anserine and carnosine concentrations. Therefore, the results of this research suggest that supplementation of swine diets with β-alanine and/or histidine is not an efficient method to increase the oxidative stability of pork.     

The effect of seasonality of the growing–finishing period on carcass,meat and fat characteristics of heavy barrows and gilts

A trial was conducted to study the effect of gender (barrows; gilts) and seasonality of growing–finishing period (S, summer; W, winter) on the carcass and meat characteristics and fatty acid (FA) profile of subcutaneous fat of pigs slaughtered at 131 kg of body weight. No significant gender × seasonality interaction was detected and the differences between genders were scarce. The S pigs had a 13.2% thinner fat depth over the Gluteus medius muscle and a higher yield of shoulders and loins by 10.6% and 10.0%, respectively than W pigs. Meat from S pigs had 32.5% lower intramuscular fat content and higher cooking losses (9.1%) and shear force (6.4%) than meat from W pigs. Subcutaneous fat from S pigs had a 7.8% higher percentage of saturated FA and 4.9% lower monounsaturated FA than that from W pigs. It is concluded that in Spanish natural-environment facilities, the seasonality of the growing–finishing period affects the carcass, and meat and fat quality of heavy pigs.