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.     

Effects of nutritional level on pork quality and gene expression of μ-calpain and calpastatin in muscle of finishing pigs

The study was designed to investigate the effects of nutritional level (control diet (CD), 14.19% crude protein, 13.81 MJ of DE/kg; low nutritional level diet (LND), 11.08% crude protein, 12.55 MJ of DE/kg) on pork quality and gene expression of μ-calpain and calpastatin in muscle of finishing pigs. The LND treatment increased drip loss (P < 0.05), had a trend to increase intramuscular fat (IMF) content (P = 0.09), decreased Warner–Bratzler shear force (WBSF) of pork (P < 0.05), improved mRNA level of μ-calpain (P < 0.05) in skeletal muscle, but had no effect on gene expression of calpastatin, compared with the CD treatment. These data suggest that a moderately reduced energy and protein diet increased pork tenderness and intramuscular fat. The increase in tenderness by LND treatment may be partly due to increased gene expression of μ-calpain in muscle.     

Diet quality in children: A function of grandparents’ feeding practices?

Grandparents are playing an increasingly important role in shaping the nutrition environment and eating behaviours of their grandchildren. Yet, research assessing the various feeding practices of grandparents and the association between grandparents’ engagement in these practices and the nutritional quality of the food consumed by their grandchild is limited. Accordingly, the present study (i) examined the feeding practices of grandparents who report providing childcare to their grandchildren, (ii) developed and tested a model linking the various practices of grandparent caregivers to the frequency with which their grandchildren consume healthy and unhealthy foods while in grandparental care, and (iii) explored the socio-demographic predictors of engagement in feeding practices. An online survey was administered to grandparents who reported providing regular care to at least one grandchild aged 3–14 years (n = 1076, 60% female, average age = 65.07 years, SD = 6.68). Grandparents reported using positive feeding practices more frequently than negative feeding practices. The developed model provided a good fit to the data and accounted for 16% of the variance in vegetable consumption, 15% in fruit consumption, 37% in savoury snack consumption, 23% in sweet snack consumption, and 35% in sugary drink consumption. Positive feeding practices were identified as being more important correlates of diet quality than negative feeding practices, with the provision of a healthy food environment and limit setting found to be associated with favourable dietary behaviours. Results suggest that grandparents should be considered important stakeholders in the promotion of healthy eating and targeted in policies and programs addressing children’s diet and obesity.     

Influence of storage period and packaging method on sliced dry cured beef “Cecina de Leon”: Effects on microbiological,physicochemical and sensory quality

Quality aspects of sliced dry-cured beef “Cecina de León” preserved in vacuum and gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂) were studied. The evolution of microbiological, physicochemical and sensory parameters were analysed during storage (210 days) at 6 °C. Although microbial counts at 60 days of the gas-packaged samples were lower than the vacuum-packed ones, they were never higher than the spoilage limit (7 log ufc/g). A slight increase (p < 0.05) in pH was observed throughout storage of “Cecina de León” packaged under vacuum and in gas mixtures. However, a decrease (p < 0.05) in a_w was observed during storage of “Cecina de León” packaged under vacuum but a_w did not vary (p > 0.05) during storage in the gas-packaged samples. No changes were observed (p > 0.05) in lightness (L¹), redness (a¹) and yellowness (b¹) in vacuum and gas packaged samples during storage. However, sensorially evaluated colour showed lower values in gas packaged samples during 30 days storage. This difference was decisive in establishing the shelf-life of “Cecina de León” slices preserved in gas mixtures (20%/80% CO₂/N₂ and 80%/20% CO₂/N₂). Therefore, from a microbiological point of view, gas mixtures are more effective in extending the shelf-life of “Cecina de León” slices. It is concluded that vacuum packaging allows longer storage than gas-packaging as it maintains a good visual appearance of “Cecina de León”, the main parameter in consumers’ perception of meat quality.     

Influence of vegetable and animal rennet on proteolysis during ripening in ewes’ milk cheese

The renewed interest in using enzymes from thistles of the genus Cynara in the making of traditional ewes’ milk cheese prompted us to investigate the effect of vegetable and animal rennet on proteolysis during ripening of Los Pedroches cheese. Casein hydrolysis was found to be much more extensive and faster in cheese made by using vegetable rennet (the amount of soluble nitrogen at 60, 80 and 100 days of ripening was more than 28% greater than that in cheese produced using animal rennet). The levels of insoluble Tyr and Trp were higher in cheese produced with vegetable rennet. PAGE, using gels containing 7 M urea, revealed decreased contents in residual α_s-CN and β-CN, as well as markedly increased levels of the more mobile components in cheese produced from vegetable rennet at the end of ripening. On the other hand, the degree of proteolysis in terms of NPN or its main components (peptides, amino acids and ammonia) was similar in cheese produced using animal or vegetable rennet.     

Effects of combined fumaric Acid-UV-C treatment and rapeseed protein-gelatin film packaging on the postharvest quality of ‘Seolhyang’ strawberries

‘Seolhyang’ strawberries were treated with fumaric acid (FA) and UV-C irradiation and packed with rapeseed protein-gelatin (RG) film containing 1% grapefruit seed extract (GSE). The initial population of total aerobic bacteria in the strawberries was 2.9 log CFU/g, while that of samples treated with FA plus UV-C and packed with RG film was 1.3 log CFU/g. For yeast and mold populations, the control had 2.6 log CFU/g, while samples treated with the combined treatment had 1.0 log CFU/g. These results suggest that combined postharvest treatment and RG film packaging can be useful for maintaining the quality of ‘Seolhyang’ strawberries.     

Effect of virtual eating environment on consumers’ evaluations of healthy and unhealthy snacks

Immersive technologies such as virtual reality and augmented reality have been recently explored in the field of food consumption studies from different perspectives. The present study utilized virtual reality technology in a within-subject experiment with three conditions to examine whether a varying virtual eating environment can alter consumers’ emotional responses (positive, negative, neutral) to the eating situation and whether the resulting emotional responses correlate with consumers’ wanting, liking, and hedonic evaluations of healthy and unhealthy snacks. In addition, the study analyzed whether a virtual eating environment that generates a positive emotional response can raise consumers’ rating of a healthy snack to the same level as an unhealthy snack consumed in a plain, unimmersed environment. The results showed a correlation between positive emotional responses and the pre-tasting evaluations of both snacks. In terms of hedonic evaluations, positive emotional responses correlated mainly with consumers’ evaluation of the unhealthy snack. When pre-tasting wanting and liking evaluations are compared between experimental conditions, the results indicate that a healthy snack is rated higher in a virtual reality environment that induces a more positive emotional response. The healthy snack was also rated at the same level as the unhealthy snack consumed in a plain environment. No differences between conditions were observed in consumers’ hedonic evaluations of the products. EEG and heart rate measurement results indicate that this might be because tasting a healthy snack generates more cognitive processing than an unhealthy snack. This might reduce the influence of the virtual eating environment on consumers’ evaluations. To conclude, virtual reality technologies might have the potential to support consumers’ eating experiences and healthy food choices by improving their evaluations of the products.     

Effects of engineered methionine in the 8Sα globulin of mungbean on its physicochemical and functional properties and potential nutritional quality

The major storage protein of mungbean, 8Sα globulin or vicilin, was engineered using site-directed mutagenesis to increase the number of methionine (Met) residues in the molecule for improvement of functional and nutritional qualities. Eight Met-rich proteins were designed and prepared to have 2 to 10 Met residues introduced in disordered regions II and IV. The designed proteins were highly expressed as soluble form in Escherichia coli. Their production level of the modified proteins was estimated to be about 30%, and was almost the same as that of 8Sα globulin wild type (WT). The modified proteins formed stable native conformation similar to WT as shown by gel filtration chromatography. They demonstrated greater stability in terms of thermal denaturation temperature and greater emulsifying ability and emulsion stability, especially the 10-Met protein, compared to the wild type. Met-rich proteins with 3, 5, and 10 Met residues had 74, 96, and 145% of nutritional requirement for Met compared with 41% for WT. Based on allergenicity prediction programs, WT and all the modified proteins had no allergenic potential.     

Effects of marination, cooking and storage on physico-chemical and microbiological properties of ready to eat trout döner kebab

The aim of this work was to investigate the use of rainbow trout (Oncorhynchus mykiss) in ready to eat döner kebab production and determine the effects of marination, cooking and storage conditions (4 and ?18 °C) on physico-chemical and microbiological properties of döner kebab. The raw trout meat, raw, cooked and stored döner kebab samples were subjected to moisture, protein, fat, ash, color, pH, cholesterol, biogenic amines, lipid oxidation, fatty acids profile, texture, microbiological and sensory analysis. The results indicated that the major fatty acids in trout döner kebab were palmitic, stearic, oleic, omega-3 and omega-6 fatty acids and unsaturated fatty acids were higher than saturated fatty acids (p < 0.05). Low biogenic amine and cholesterol contents were determined in döner kebab. It was found that ?18 °C of storage temperature was more effective than 4 °C for inhibition of lipid oxidation and microbial growth in trout döner kebab (p < 0.05). While cooking affected parameters evaluated (p < 0.05), marination did not have any significant effect. The study results indicated that using rainbow trout meat in döner kebab production could be beneficial to provide healthy meat products without posing any acceptability problems in terms of quality factors. This is the first paper to be reported on physico-chemical and microbiological properties of döner kebab produced with rainbow trout and effects of marination, cooking and different storage temperatures on these physico-chemical and microbiological properties.     

Pasture allowance,duration, and stage of lactation—Effects on early and total lactation animal performance

Pasture availability in early spring can be limited due to climatic effects on grass production, increasing the likelihood of feed deficits in early lactation of spring-calving pasture-based systems. We hypothesized that restricting pasture allowance (PA) when animals are at peak milk production will have more negative implications on milk production compared with restricting animals before this period. A total of 105 cows were assigned to 1 of 7 grazing treatments from March 14 to October 31, 2016 (33 wk). The control treatment was offered a PA to achieve a postgrazing sward height > 3.5 cm and mean pasture allowance of 15.5 kg of dry matter per cow. The remaining treatments were offered a PA representing 60% of that offered to the control for a duration of 2 or 6 wk from March 14 (mid-March; MMx2 and MMx6), March 28 (end of March; EMx2 and EMx6), or April 11 (mid-April; MAx2 and MAx6). Within grazing treatment, animals were also assigned to 1 of 2 calving dates (early and late) based on days in milk (DIM) on March 14. Early calved (EC) cows were ≥36 DIM, while late calved (LC) were ≤35 DIM. Restricting PA for 2 and 6 wk reduced daily milk yield (?1.6 and ?2.2 kg/cow, respectively), cumulative milk protein yield (?4.0 and ?6.3 kg/cow, respectively), and cumulative milk solids yield (?5.8 and ?9.5 kg/cow, respectively) in the first 10 wk of the experiment. Daily milk yield was similar across the treatments at the end of the 33-wk period (16.8 kg/cow, average of all treatments), as was daily milk solids yield (1.40 kg/cow). Cows in the EC group produced less milk over the first 10 wk of the experiment (20.0 kg/cow per day) compared with the LC animals (22.1 kg/cow per day). However, body weight was greater (+15 kg/cow) in the EC animals compared with the LC, while body condition score was similar (2.85). This outcome indicates that animals that are restricted later in early lactation (circa onset of peak milk production) partition a greater proportion of available energy to maintenance, resulting in greater losses in milk production. These data indicate that despite the immediate reduction in milk production, restricting intake of grazing cows to 80% of that required to achieve spring grazing targets for postgrazing sward height for up to 6 wk may be used as a method of managing short-term pasture deficits on farm with minimal effects on total lactation performance.     

Effects of low-dose γ-irradiation and modified atmosphere packaging on shelf-life and quality characteristics of saffron (Crocus Sativus Linn) in Iran

Effects of different packaging methods (air and modified atmosphere packaging) combined with irradiation (0.0, 1.0, and 2.0 kGy) on the preservation of saffron samples stored at room temperature for up to 60 days were investigated. Microbial analysis of aerobic bacteria, coliform, Escherisha coli, mold, and yeast was carried out. Among the analyzed bacteria, coliforms were most sensitive to γ-radiation. Based on sensory analyses and physicochemical analyses as a whole, the saffron samples packaged under modified atmosphere and irradiated with dose 2.0 kGy were acceptable under storage for 60 days, compared to 30 days for air-packaged non-irradiated samples.     

Effect of probiotic co-cultures on physico-chemical and biochemical properties of small ruminants’ fermented milk

Small ruminants' fermented probiotic milk is an alternative to fermented cows' milk, especially because of the monounsaturated/polyunsaturated fatty acid profiles. The technological and biochemical potential of Bifidobacterium and Lactobacillus co-cultures, with or without inulin, on goats' and ewes' milk was assessed. Microbial stability, lactose consumption, organic acid production, proteolytic parameters and conjugated linoleic acid (CLA) production in situ, were followed in ewes' and goats’ fermented milk (EFM and GFM, respectively) over 21 days at 4 °C; technological feasibility for probiotic fermented milk production was shown. In EFM, all co-cultures presented high viable cell numbers (>7.0 log cfu mL⁻¹) throughout storage, presenting faster acidification capacities and higher CLA isomer levels than in GFM. Inulin had no impact on probiotic growth, yet contributed to storage stability. CLA isomers and proteolysis indices were co-culture dependent traits: for example, co-culture of Bifidobacterium animalis B94 with Lactobacillus acidophilus L10 registered the best CLA-production in GFM.     

Effects of muscle α-tocopherol level and surface microbiological contamination on retail caselife of fresh beef from the US, Japan and Australia

This study evaluated effects of dietary supplementation of vitamin E (1000 IU vitamin E/daily for 100 days prior to harvest) to fed cattle on retail caselife performance of fresh US beef in an export market (Japan). Economic performance (monetary losses associated with color deterioration) for US beef from vitamin E supplemented cattle vs beef from non-vitamin E supplemented cattle was contrasted. An additional, controlled study was performed to compare muscle α-tocopherol concentrations, color changes and microbiological growth for fresh beef derived from vitamin E supplemented US cattle and fresh beef from cattle with an unknown history, but from other countries. Australian strip loin steaks had the highest muscle α-tocopherol concentrations (4.6 μg/g tissue), followed by US strip loin steaks derived from vitamin E supplemented cattle (3.4 μg/g tissue) and Japanese strip loin steaks (2.8 or 2.5 μg/g tissue). US strip loin steaks from non-vitamin E supplemented cattle had the lowest (p<0.05) α-tocopherol levels (1.7 μg/g tissue). Aerobic plate counts and total coliform counts were generally low at 0 days of retail display, and they changed similarly among treatments over 6 days of display, regardless of the country of origin of the beef. Vitamin E supplementation of US cattle reduced total Japanese retail store losses due to discoloration of US beef, in yen, by 5.2 percentage points (p<0.05), saving Japanese retailers US $0.24/kg. Data suggest that US beef-normally perceived, in Japan, to discolor more quickly in the retail display case than beef from Australia-would compete more favorably, in shelf-life, with beef from other countries if it was derived from cattle that had been fed supplemental vitamin E.     

Effects of ozonation on microbiological,chemical and sensory attributes of vacuum-packaged rainbow trout stored at 4±0.5°C

The effects of ozone in aqueous solution on the shelf life of whole, vacuum-packaged rainbow trout, stored under refrigeration (4±0.5°C) were studied by monitoring the microbiological, chemical and sensory changes for a period of 15 days. Vacuum-packaged non-ozonated trout served as the control sample. Ozonation affected populations of bacteria namely, mesophilic aerobic bacteria, Pseudomonas spp. and H₂S-producing bacteria until day 11 of storage, Brochothrix thermosphacta, lactic acid bacteria and Enterobacteriaceae until day 8 of storage. Trimethylamine (TMA) values of all rainbow trout samples remained low (<3 mg N/100 g) until day 11 of storage, and then increased to 12.2, 8.9 and 4.7 mg N/100 g for the control and the samples ozonated for 60 and 90 min, respectively on day 15 of storage. Total volatile basic nitrogen (TVB-N) values remained relatively constant (20–25 mg N/100 g) until day 11 of storage, but increased to 61.1, 37.6 and 39.4 mg N/100 g flesh for the control and ozonated specimen for 60 and 90 min, respectively on day 15 of storage. Thiobarbituric acid (TBA) values remained relatively constant (1–3 mg MA/kg flesh) until day 12 of storage but increased to 8.4, 6.4 and 3.8 mg MA/kg flesh on day 15 of storage for the control and the ozonated trout for 60 and 90 min, respectively. Sensory evaluation (odor, taste and texture) of cooked rainbow trout showed a very good correlation with bacterial populations. On the basis of both sensory and microbiological data, a shelf life of 10 and 12 days was obtained for ozonated, vacuum-packaged and refrigerated rainbow trout at 60 and 90 min, respectively.     

Effects of dietary digestible energy concentration on growth, meat quality, and PPARγ gene expression in muscle and adipose tissues of Rongchang piglets

This study investigated the effects of dietary digestible energy (DE) concentration (3.20, 3.40, 3.60 & 3.80 Mcal/kg) on growth, meat quality, and PPARγ gene expression in muscle and adipose tissues of Rongchang piglets. There was a quadratic increase in average daily gain and a linear decrease in the ratio of feed intake and gain as dietary DE increased (P < 0.05). Increasing dietary DE resulted in a linear increase of back fat thickness and intramuscular fat content (P < 0.05). A significant linear or quadratic effect (P < 0.01) was detected for shearing force. Increasing dietary DE linearly enhanced the expression of PPARγ in adipose tissues (P < 0.01). These data suggest that dietary DE had an impact on carcass and meat quality of Rongchang piglets. This could be partly due to the increased gene expression of PPARγ in adipose tissues, which may regulate the fat deposition of whole body.     

Effect of pretreatments and retort process on characteristics and sensory quality of edible bird’s nest beverage

Edible bird ’ s nest (EBN) flakes were pretreated using sodium alginate (AG) in the presence of different divalent cross-linking agents before retorting at different temperatures (118 and 121 °C). Protein was the dominant component (58.61 g 100 g⁻¹, wet weight basis), followed by carbohydrate (24.38 g 100 g⁻¹, wet weight basis). Fourier transform infrared spectra (FTIR) showed the interaction between 1.0 g 100 mL⁻¹ AG with protein as induced by cross-linking agents including 0.5 g 100 mL⁻¹ calcium chloride, 1.0 g 100 mL⁻¹ calcium lactate or 1.0 g 100 mL⁻¹ magnesium chloride. Those alginate gels formed in beverage (EBNB) could withstand retorting at both temperatures. All pretreated EBN yielded EBNB with higher hedonic liking scores than control and non-retort process. Pretreatment of ENB using 1.0 g 100 mL⁻¹ AG and 1.0 g 100 mL⁻¹ calcium lactate before retorting at 121 °C rendered safe ready-to-drink EBNB with high hedonic liking score of all attributes.