Effect of ascorbic acid and protein concentration on the molecular weight profile of bovine serum albumin and β-lactoglobulin by γ-irradiation

The effects of ascorbic acid and protein concentration on the molecular weight size distribution of BSA and β-lactoglobulin were examined after irradiation of proteins at various doses. Gamma-irradiation of protein solutions caused disruption of the ordered structure of protein molecules resulting in degradation, cross-linking, and aggregation of the polypeptide chains. SDS–PAGE and gel permeation chromatography study showed that ascorbic acid protected the aggregation and degradation of proteins by scavenging oxygen radicals produced by irradiation and the effect of irradiation on protein conformation was more significant at lower concentrations of proteins.     

Influence of processing on the generation of γ-aminobutyric acid in green coffee beans

A determination of the concentrations of free amino acids in differently processed green coffees indicated the nonprotein amino acid -aminobutyric acid (GABA), a well-known plant stress metabolite, to be present in raw coffee beans (Coffea arabica L.) in significantly varying amounts. The GABA content of unwashed Arabica beans (green coffee produced by the dry processing method) was always markedly higher than that of washed Arabicas (wet processing method) as well as that of untreated seeds. This result underlined the assumption that during postharvest treatment a significant metabolism occurs within coffee seeds. A putative relation between drought stress of the coffee seeds and postharvest treatment methods is discussed. The GABA content of green coffee beans may serve as a potent tool to characterize the type of postharvest treatment applied in coffee processing.     

Effect of phosphate, ascorbic acid and α-tocopherol injected at one-location with tumbling on quality of roast beef

The purpose of this study was to evaluate if continuous non-vacuum or vacuum tumbling improves the quality of roast beef utilizing the one location injection. Basically, fresh roast beef treated by one location injection with tumbling had significantly different quality compared to non-tumbled ones. However, the cooked roast beef did not significantly exhibit better quality due to tumbling. There was insignificant difference of TBARS value for whole meat among treatments at day 0. The control had significantly higher TBARS value compared to roast beef with non-vacuum and vacuum tumbled samples at day 2. At 4, 7 and 14 days of refrigerated storage, the control maintained the significantly highest values when compared to the other treatments that had similar TBARS values. The addition of three antioxidants was the major contributor to lipid stability of the cooked roast beef.     

Effect of γ-polyglutamate on the rheological properties and microstructure of tofu

The effects of γ-polyglutamates with different concentrations (0.1%, 0.15%, 0.2%) and molecular weights (high, medium, low) addition on the rheological properties, microstructure, and syneresis of tofu were studied. The addition of γ-polyglutamate increased the gelation time, and decreased the storage modulus (G′) and the loss modulus (G″) of tofu. The molecular weight and concentration of γ-polyglutamate effectively changed the rheological properties of tofu. The network of tofu without γ-polyglutamate addition was constructed by fine strands in a dense arrangement as seen by using scanning electron microscope. However, the addition of γ-polyglutamate reduced the thickness of the strands in tofu network. Tofu syneresis was also reduced by the addition of γ-polyglutamate. Increase the concentration of γ-polyglutamate significantly decreased the syneresis of tofu. This trend was more evident on the tofu with high molecular weight γ-polyglutamate.     

Modification of bean starch by γ-irradiation: Effect on functional and morphological properties

Starches isolated from Red, White, Yellow and Black Kidney beans were treated by γ-irradiation doses of 5, 10 and 20 kGy. Physicochemical, morphological and pasting properties of irradiated bean starches were investigated. Microscopic observation under scanning electron microscope (SEM) showed that some of the bean starch granules were destroyed by γ-irradiation and the breakage was greater at a higher dose (20 kGy). Physicochemical properties differed significantly and showed strong dose-dependent relationship. Carboxyl content, solubility, water absorption capacity and transmittance increased, whereas swelling power, apparent amylose content, syneresis and pasting properties decreased upon the irradiation of kidney bean starch. Radiation doses were positively correlated with water absorption capacity and solubility index and negatively correlated with swelling index, peak viscosity, trough viscosity, breakdown and final viscosity. There were high positive correlations between pasting properties. X-ray diffraction pattern remained same upon irradiation but a decrease in crystallinity was observed with increasing irradiation dose.     

Effect of irradiation on Salmonella survival and quality of 2 varieties of whole green onions

Abstract: Two varieties of green onions, Banner and Baja Verde, were inoculated with a cocktail of 3 Salmonella strains using dip and spot inoculation and irradiated at 0, 0.3, 0.6, 0.9, and 1.2 kGy using electron beam. Salmonella survivors were enumerated using a XLD underlay/TSAYE overlay plating method. The D values were in the range of 0.26 to 0.32 kGy depending on variety but not on the method of inoculation. This indicated that a 5‐log reduction of Salmonella can be achieved at a dose of 1.6 kGy. For the quality study, both varieties of green onions were irradiated at 0, 1.5, 2.0, and 2.5 kGy and evaluated for changes in microbial counts, color, texture, and visual quality during storage at 4 °C. Irradiation reduced total plate counts and psychrotrophs by 3 logs. Although the counts increased during storage, they did not exceed the initial counts of control. No significant difference was observed in color and texture between irradiated samples and control. The control maintained good visual quality for about 13 d as compared to 15 d for 1.5 and 2.5 kGy samples. The 2.0 kGy samples maintained good visual quality for 17 d suggesting that irradiation can increase shelf life by reducing spoilage microorganisms but higher doses can be detrimental to quality. At the dose levels required to achieve a 5‐log reduction in Salmonella, the shelf life of whole green onion can be extended. This study shows that irradiation can be used to enhance safety without adverse effects on quality.     

Effect of γ-irradiation on physical quality attributes and identification properties of different sauces

Gamma-irradiated (0, 1, and 10 kGy) ketchup (KTP), barbeque sauce (BBQ), and sweet chili sauce (SWC) were identified using photostimulated-luminescence (PSL) and thermoluminescence (TL) analysis and characterized for physical properties like Brix, consistency, and color. PSL-based screening showed negative results for all nonirradiated samples, while intermediated results were found for irradiated samples. Routine density separation method for mineral extraction provided better TL results; however, alkaline and acid hydrolysis could ease the process with acceptable results. A slight decrease in consistency of all the samples was observed. Brix of KTP remained unchanged, while increase of same was obvious in BBQ and SWC following irradiation. The Hunter L* value of the γ-irradiated sauces decreased except SWC samples, and the a* and b* values showed a general increase compared to the non-irradiated samples. The studied methods have potential to successfully identify and characterize the irradiated sauces for technical and regulatory requirements.     

Effect of acid concentration and treatment time on acid–alcohol modified jackfruit seed starch properties

The properties of starch extracted from jackfruit (Artocarpus heterophyllus Lam.) seeds, collected from west Assam after acid–alcohol modification by short term treatment (ST) for 15–30 min with concentrated hydrochloric acid and long term treatment (LT) for 1–15 days with 1 M hydrochloric acid, were investigated. Granule density, freeze thaw stability, solubility and light transmittance of the treated starches increased. A maximum decrease in the degree of polymerisation occurred in ST of 30 min (2607.6). Jackfruit starch had 27.1 ± 0.04% amylose content (db), which in ST initially decreased and then increased with the severity of treatment; in LT the effect was irregular. The pasting profile and granule morphology of the treated samples were severely modified. Native starch had the A-type crystalline pattern and crystalline structure increased on treatment. FTIR spectra revealed slight changes in bond stretching and bending. Colour measurement indicated that whiteness increased on treatment. Acid modified jackfruit seed starch can have applications in the food industry.     

Effect of γ-irradiation on bioactivity, fatty acid compositions and volatile compounds of clary sage seed (Salvia sclarea L.)

Clary sage seeds (Salvia sclarea L.) were obtained from plants cultivated, and 2.5, 4.0, 5.5, and 7.0 kGy doses of γ-irradiation were applied to the clary sage seeds. They were then analyzed for their protein, ash, oil and dry matter contents, and fatty acid composition. Additionally, the total phenolic contents, antiradical, antioxidant activities, and volatile compounds of the clary sage seed extract were determined. There was no significant difference in protein content. However, the moisture, oil, and ash contents of the samples were affected by irradiation. While the 7 kGy dose had a positive effect on the total phenolic content and antiradical activity of the sage seed extract, all doses have negative effects on the antioxidant activity of the sage seed. The main fatty acid of the sage seed was remarkably found as α-linolenic acid. The four irradiation levels caused significant differences in fatty acid composition by affecting all fatty acids except palmitic, palmitoleic, and eicosenoic acids. The dominant volatile compounds of control sage seed were found as β-pinene (18.81%) and limonene (15.60%). Higher doses of the irradiation decreased volatile components of sage seed. Clary sage seed including high omega-3 can be irradiated with low doses (≤ 2.5 kGy) of γ-irradiation. PRACTICAL APPLICATION: Clary sage is one of the most popular Salvia species in Turkey and many countries. Clary sage seed has approximately 29% oil content and this oil contains >50% of α-linolenic acid. γ-Irradiation is widely applied in the preservation of spice quality. The present study shows that the antioxidant activity of the clary sage seed is decreased by γ-irradiation. Additionally, higher doses of irradiation also decreased the volatile components of sage seed. Therefore, we suggest that clary sage seed which includes high levels of omega-3 should be irradiated with low doses (≤ 2.5 kGy) of γ-irradiation.     

Effect of ferulic acid and α-tocopherol antioxidants on properties of sodium caseinate edible films

Edible films, based on sodium caseinate containing three different concentrations of ferulic acid or α-tocopherol (20, 40 and 60 mg/g sodium caseinate), were obtained in order to evaluate the effect of these compounds on properties of the caseinate matrices. Special emphasis was placed on their effect on the films’ oxygen barrier properties, which are decisive in the prevention of the oxidation of foods containing lipids. Films were characterized as to their tensile, optical and surface properties as well as their barrier properties to water vapor, oxygen and aroma compounds (n-hexanal and n-hexanol). Ferulic acid was more efficient at reducing oxygen and n-hexanal permeability than α-tocopherol. Although ferulic acid slightly increased the stiffness of films at low concentration, in general, both antioxidants slightly reduce mechanical resistance, water vapor permeability, gloss and transparency of the films.     

Effect of added α-ketoglutaric acid,pyruvic acid or pyridoxal phosphate on proteolyis and quality of Cheddar cheese

Cheddar cheese curds were supplemented with 1, 5 or 20 g of α-ketoglutarate or pyruvic acid or 1.2 g pyridoxal-5¹-phosphate/kg cheese curd. The higher levels of keto-acids (5 or 20 g/kg curd) caused undesirable changes in the physico-chemical properties of resultant cheese. All levels of α-ketoglutarate reduced the pH of the cheese and promoted syneresis during pressing, while pyruvic acid increased the pH of the cheese. The numbers of starter and non-starter lactic acid bacteria were not affected by the addition of keto-acids or pyridoxal-5¹-phosphate. α-Ketoglutarate or pyruvic acid, at 1 g/kg, or pyridoxal-5¹-phosphatase, at 1.2 g/kg cheese curd, did not influence primary proteolysis in the cheese. The highest and lowest concentrations of total and individual free amino acids were found in the cheeses treated with pyruvic acid or α-ketoglutarate, respectively. The concentrations of most amino acids were lower in the cheeses treated with pyridoxal-5¹-phosphate than in the control. The results of this study suggest that α-ketoglutarate and pyridoxal-5¹-phosphate enhanced the degradation of most amino acids in Cheddar cheese while pyruvic acid promoted the formation of amino acids. The cheeses treated with α-ketoglutarate were more mature than the control cheese of the same age while pyruvic acid-treated cheese had a better flavour than the control.     

Control of nutritional labels in beverages with added vitamins: screening of β-carotene and ascorbic acid contents

Simple, rapid and inexpensive methods were used for the determination of β-carotene and ascorbic acid, while checking recovery and precision with samples, and calibration data and detection levels with standards. These methods involved direct injection of the beverage into an HPLC with an UV-Visible detector. The results obtained with 13 beverages, with different β-carotene and ascorbic acid levels added, did not show good agreement between the vitamin levels on the labels and the levels determined. Found levels, in virtually all drinks, were much higher than those stated on the nutritional label.     

Influence of preprocessing methods and fermentation of adzuki beans on γ-aminobutyric acid (GABA) accumulation by lactic acid bacteria

The effects of pre-processes (immersing, germinating, and cold shock) and fermentation conditions of adzuki beans on γ-aminobutyric acid (GABA) accumulation using mixed cultures of Lactococcus lactis and Lactobacillus rhamnosus were investigated in this study. Among the preprocessing methods, cold shock treatment resulted in the highest observed GABA content (201.2 mg/100 g); a 150-fold increase compared to the non-treated adzuki beans. The LAB strains grew rapidly in cold-treated adzuki bean substrates and reached 10⁸ cfu/ml after 24 h of fermentation at 30 °C. After optimization, the GABA yield reached 68.2 mg/100 ml; a 20-fold increase compared to the non-fermentation yield. The viable cell counts of LAB remained above 10⁸ cfu/ml after 28 days of storage at 4 °C. Our results suggest that the combination of cold shock pretreatment and fermentation by LAB may be used for the preparation of adzuki beans with high GABA content, which can then be used as a natural resource of functional foods.     

Effects of green tea catechin on the lipid oxidation,volatile compound formation,and losses of retinol and α-tocopherol in whole milk during light illumination as compared with ascorbic acid

Effects of green tea catechin (GTC, catechin content 61.4%) on the formations of hydroperoxide, malonaldehyde, and volatile compounds, and losses of retinol and tocopherol in milk during light illumination were studied. GTC showed surprisingly high protective activity of milk photooxidation, in a dose dependent manner. GTC at 25 ppm exerted 82.1 and 75.0% inhibitions of hydroperoxide and malonaldehyde formation during 30 h light illumination, respectively. GTC at 25 ppm exerted 88.7 and 94.3% inhibition of hexanal and heptanal formation in milk during 30 h light illumination, respectively. The 25 ppm GTC greatly suppressed the losses of retinol and α-tocopherol, showing 53.6 and 58.7% protections of their losses in milk after 12 h light illumination, respectively. The protective activity of GTC was at least 4 times higher than ascorbic acid. The inhibitory activities of GTC and ascorbic acid against the photooxidation of milk were in consistent with their singlet oxygen quenching abilities.     

Effect of dietary α-linolenic acid and vitamin E on the fatty acid composition, storage stability and sensory traits of rabbit meat

The synergistic effect of dietary linolenic acid and vitamin E on the oxidative stability and nutritional and eating characteristics of fresh and stored rabbit meat was studied. One-hundred hybrid male rabbits were divided into two homogenous groups and fed ad libitum two diets differing in the amount of sunflower and flaxseed and in the level of α-tocopherol, as follows: control diet: 0.08 kg kg(-1) sunflower, 50 mg kg(-1) α-tocopheryl-acetate and LNA-VE diet: 0.08 kg kg(-1) flaxseed, 200 mg kg(-1) α-tocopheryl-acetate. At 85 days, 20 rabbits per group were slaughtered and the thiobarbituric-acid reactive substances (TBA-RS), chemical composition, fatty acid profile and sensory quality were assessed on the longissimus dorsi muscles (fresh and stored for 8 days at 4?°C). The proximate composition of the fresh muscle was not significantly affected by the dietary treatment. Rabbits fed the LNA-VE diet showed a good capability to elongate and desaturate linolenic acid and this diet enriched the n-3 PUFA content of the meat without affecting its peroxidative stability. The sensory quality of the fresh and stored muscle was slightly affected by the dietary treatment, even though final tenderness (fresh meat) and overall acceptability (stored meat) of the LNA-VE rabbits showed significantly higher scores.     

Effects of rumen-protected γ-aminobutyric acid on performance and nutrient digestibility in heat-stressed dairy cows

This experiment was conducted to investigate the effects of rumen-protected γ-aminobutyric acid (GABA) on performance and nutrient digestibility in heat-stressed dairy cows. Sixty Holstein dairy cows (141 ± 15 d in milk, 35.9 ± 4.3 kg of milk/d, and parity 2.0 ± 1.1) were randomly assigned to 1 of 4 treatments according to a completely randomized block design. Treatments consisted of 0 (control), 40, 80, or 120 mg of true GABA/kg of dry matter (DM). The trial lasted 10 wk. The average temperature-humidity indices at 0700, 1400, and 2200 h were 78.4, 80.2, and 78.7, respectively. Rectal temperatures decreased linearly at 0700, 1400, and 2200 h with increasing GABA concentration. Supplementation of GABA had no effect on respiration rates at any time point. Dry matter intake, energy-corrected milk, 4% fat-corrected milk, and milk fat yield tended to increase linearly with increasing GABA concentration. Supplementation of GABA affected, in a quadratic manner, milk protein and lactose concentrations, and milk protein yield, and the peak values were reached at a dose of 40 mg of GABA/kg. Milk urea nitrogen concentration responded quadratically. Total solids content increased linearly with increasing GABA concentration. Supplementation of GABA had no effect on milk yield, lactose production, total solids, milk fat concentration, somatic cell score, or feed efficiency. Apparent total-tract digestibilities of DM, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber were similar among treatments. These results indicate that rumen-protected GABA supplementation to dairy cows can alleviate heat stress by reducing rectal temperature, increase DM intake and milk production, and improve milk composition. The appropriate supplemental GABA level for heat-stressed dairy cows is 40 mg/kg of DM.     

Effect of alternative C2 carbon sources on the growth, lipid, and γ-linolenic acid production of spirulina (Arthrospira platensis)

The influence of different organic carbon sources (glucose, ethanol, and acetic acid) at different concentrations (0.1, 0.5, and 1.0 g/L for batch and 1.0, 2.0, and 3.0 g/L for fed-batch) were studied in the mixotrophic production (using both light and carbon source) of γ-linolenic acid (GLnA) by spirulina (Arthrospira platensis). The obtained spirulina was analyzed in terms of biomass, lipid, and GLnA production. In the batch media, increasing the concentrations of glucose, ethanol, and acetic acid led to an increase in the biomass, lipid, and GLnA production. However, carbon sources at concentrations greater than 1.0 g/L in fed-batch media appeared to have no significant effects on the above parameters. It was also demonstrated that biomass, lipid, and GLnA production using ethanol and acetic acid could be as good as those achieved with the classic glucose-based culture media.     

Effect of Co γ-irradiation on postharvest quality and selected enzyme activities of Pleurotus nebrodensis

Freshly harvested Pleurotus nebrodensis fruit bodies were exposed to four different doses (0.8-2.0 kGy) of ⁶⁰Co γ-irradiation and various physiological changes associated with postharvest deterioration, as well as the activities of selected enzymes (proteinase, polyphenoloxidase, superoxide dismutase, catalase) thought to play a role in the process of deterioration, were monitored during 22 days of subsequent storage at 4 °C and 65-70% relative humidity. An irradiation dose of 1.2 kGy significantly delayed (by 6-9 days) the onset of fruit body softening, splitting and browning compared with non-irradiated controls and test samples subjected to lower or higher irradiation doses. Irradiation with 1.2 and 1.6 kGy also had a positive effect on other indicators of mushroom tissue senescence, resulting in smaller decreases in soluble protein levels and more protracted increases in proteinase activity. Peak levels of polyphenoloxidase activity, widely recognized as causing postharvest browning of mushroom tissue, were also significantly lower (P < 0.05) in fruit bodies exposed to 1.2 kGy compared with non-irradiated controls. Our data increase our understanding of the effects of γ-irradiation on the biochemical changes associated with postharvest deterioration in P. nebrodensis, and improve the prospects of more targeted strategies for extending the shelf life of both this and other mushrooms.     

Effect of adzuki bean sprout fermented milk enriched in γ-aminobutyric acid on mild depression in a mouse model

This study focused on the ability of adzuki bean (Vigna angularis) sprout fermented milk, which is rich in γ-aminobutyric acid (GABA), to relieve anxiety and mild depression. A high-yield GABA-producing strain, Lactobacillus brevis J1, from a healthy cow was screened, and its physiological and probiotic properties were evaluated. The effect of adzuki bean sprout fermented milk was investigated in vivo in a chronic depression mouse model. The results showed that Lb. brevis J1 had excellent probiotic properties, grew well at low pH and 3% NaCl, and adhered to the surface of HT-29 cells. The GABA-enriched (241.30 ± 1.62 µg/mL) adzuki bean sprout fermented milk prepared with Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus plantarum, and Lb. brevis J1 can reduce and possibly prevent mild depression-like symptoms in mice (C57/B6) by increasing social interaction and enhancing the pleasure derived from movement. The research revealed that the GABA_B-cyclic AMP-protein kinase A-cAMP-response element binding protein (GABA_B-cAMP-PKA-CREB) signaling pathway was related to the depression-like symptoms and that levels of 5-hydroxytryptamine, norepinephrine, and dopamine in the hippocampus of mice increased after treatment with the adzuki bean sprout fermented milk. Our results suggest that GABA-enriched dairy products have the potential to prevent or treat mild depression-like symptoms in mice, which suggests a new approach for a dietary therapy to treat chronic social stress.