Quality and shelf life evaluation of emulsion and restructured buffalo meat nuggets at cold storage (4±1°C)

The study was aimed at comparing the physico-chemical characteristics and texture profile of emulsion and restructured buffalo meat nuggets (BMN) and assessing their shelf life at refrigeration temperature (4±1°C). The stability of restructured batter was significantly lower than that of the emulsion form. Emulsion nuggets (EN) had significantly higher product yield, fat content and calories while restructured nuggets (RN) had significantly higher moisture and protein contents. Texture profile analysis revealed that RN had significantly higher cohesiveness, gumminess, chewiness and shear force values. Differences in TBARS values for emulsion and restructured nuggets were not significant at any particular storage time. Throughout storage, counts for mesophilic, psychrotrophic and coliforms did not exceed log(10)3.09 and 3.44cfu/g, log(10)2.23 and 2.11cfu/g, log(10)1.30 and 1.30cfu/g for emulsion and restructured buffalo meat nuggets, respectively. In spite of a higher overall acceptance for EN initially, panelists rated them considerably lower compared to RN during subsequent storage. Buffalo meat nuggets were acceptable for at least 20 days in cold storage (4±1°C) under aerobic conditions in polypropylene bags.     

Effect of different binders on the quality of enrobed buffalo meat cutlets and their shelf life at refrigeration storage (4±1°C)

To enhance the binding and quality of enrobed buffalo meat cutlets (EBMC), a meat emulsion at 0%, 15%, 20% and 25% replaced the cooked meat in the formulation. Emulsion containing products had significantly higher moisture contents and texture scores compared to the control. Emulsion at 20% level could be incorporated in enrobed buffalo meat cutlets to enhance their quality. Addition of 1% egg white powder improved the quality of EBMC compared to control, while a 3% level had adverse effect on the sensory attributes despite giving higher product yield and lower shrinkage. Cutlets with refined wheat flour had significantly higher protein and fat contents. It had also higher acceptability followed by corn flour, potato starch and tapioca flour. TBARS of enrobed samples remained lower than controls throughout the storage period. Mesophilic count remained below log3cfu/g for both samples during storage. Uncoated products and enrobed products were acceptable up to 10th and 15th day, respectively. Enrobing of buffalo meat cutlets improved their acceptability and shelf life under refrigeration storage.     

Quality changes and shelf life of imported vacuum-packaged beef chuck during storage at 0°C

The objective of this study was to investigate differences in adipose tissue fatty acid composition among stress genotypes as well as to determine relationships of those fatty acids with performance, carcass and meat quality traits. Haplotypic analysis of parents and offspring was employed to assign 48 pigs to three stress genotypes of swine. Individual fatty acid profiles were determined on subcutaneous backfat. Stress genotype had a significant effect on the proportions of C14:0 (P<0.05), C16:0 (P<0.10), C16:1 (P<0.05) and C18:0 (P<0.05) fatty acids. After adjusting for stress and gender, there was a negative correlation between backfat thickness and essential fatty acids (linoleic and linolenic) (P<0.001). In contrast, the correlation of loin muscle area with C18:2 (P<0.01) and C18:3 (P<0.001) was positive. The degree of fat firmness was negatively correlated to the proportion of total unsaturated fatty acids (P<0.01). No significant correlations were observed between fatty acid contents and lean meat quality traits.     

Effect of dipping in pomegranate (Punica granatum) fruit juice phenolic solution on the shelf life of chicken meat under refrigerated storage (4°C)

An experiment was conducted to evaluate the effect of dipping in pomegranate fruit juice phenolics (PFJP) solution on the shelf life of chicken meat held under refrigerated storage at 4°C. Breast muscle obtained from spent hens was dipped (1:2w/v; muscle: liquid) in sterile water or in sterile water with 0.02% (v/v) PFJP, packed, stored at 4°C for 28 days and samples were analyzed on 2 days of intervals. Thiobarbituric acid reactive substance values were lower in samples treated with PFJP. Total sulfhydryl and protein bound sulfhydryl content values were higher in samples treated with PFJP. Microbial quality evaluation showed that aerobic and psychrotrophic counts were higher in samples treated without PFJP. Sensory evaluation revealed that acceptability level of samples treated without PFJP decreased on 12th day of storage. It is concluded that spent hen breast meat samples dipped in 0.02% PFJP reduced protein oxidation and inhibited microbial growth and sensorily acceptable up to 12 days of refrigerated storage at 4°C.     

Influence of edible coating on shelf life and quality of “Picota” sweet cherries

Concentrations of 10, 20 and 30 g/l of an edible coating based on derivatives of fatty acids and polysaccharides in alcohol solution were assayed to determine the effect on alteration of respiratory metabolism, control of transpiration and maintenance of post-harvest quality of Picota cherries. Treatment with 10 and 20 g/l coatings reduced the respiratory intensity of the fruits and attenuated the respiratory stress induced by low storage temperatures. After 2 weeks in storage at 0 °C plus 48 h at 20 °C, no off-flavours were detected, nor were there significant treatment-induced levels of ethanol and acetaldehyde. The weight loss of fruits during storage at 0 and 20 °C was inversely proportional to the concentration of the coating used. After storage, the fruits treated with concentrations of 10 and 30 g/l were shinier, more turgid and more attractive than the controls. None of the treatments produced significant changes in the evolution of quality parameters during storage, and they may therefore constitute an alternative technology to modified atmosphere packaging as currently used.     

Development of shelf stable pork sausages using hurdle technology and their quality at ambient temperature (37±1°C) storage

Shelf stable pork sausages were developed using hurdle technology and their quality was evaluated during ambient temperature (37±1°C) storage. Hurdles incorporated were low pH, low water activity, vacuum packaging and post package reheating. Dipping in potassium sorbate solution prior to vacuum packaging was also studied. Reheating increased the pH of the sausages by 0.17units as against 0.11units in controls. Incorporation of hurdles significantly decreased emulsion stability, cooking yield, moisture and fat percent, yellowness and hardness, while increasing the protein percent and redness. Hurdle treatment reduced quality deterioration during storage as indicated by pH, TBARS and tyrosine values. About 1 log reduction in total plate count was observed with the different hurdles as were reductions in the coliform, anaerobic, lactobacilli and Staphylococcus aureus counts. pH, a(w) and reheating hurdles inhibited yeast and mold growth up to day 3, while additional dipping in 1% potassium sorbate solution inhibited their growth throughout the 9 days storage. Despite low initial sensory appeal, the hurdle treated sausages had an overall acceptability in the range 'very good' to 'good' up to day 6.     

Effect of α-tocopherol on lactone formation in marbled beef and changes in lactone volatility during storage

Dynamic-headspace sampling with a standard-addition method was employed to quantitatively analyze aliphatic lactones in rendered fat from marbled beef and to evaluate the effect of the matrix on volatility. Further, the effects of different levels of the antioxidant α-tocopherol on lactone formation were examined. The slopes of the linear regression curves from the standard-addition method were significantly changed (P < 0.05 or 0.01) for all lactones after storage, with the exception of γ-octalactone, indicating the volatility of the longer-chain lactones were increased after storage. The concentrations of γ-lactones were increased after 7 d of storage at 2 °C (P < 0.01), and the α-tocopherol content in the meat affected the formation of γ-octalactone (P < 0.05) and γ-nonalactone (P < 0.01). The greatest increase was observed for γ-nonalactone in the lowest α-tocopherol (2.9 ppm) group: the concentration of 51.4 ppb was 11.7-fold higher than that before storage. Meanwhile, δ-tetradecalactone in the highest α-tocopherol (28.8 ppm) group showed the highest concentration for the lactones at 415.8 ppb, which was 2.6-fold higher than the concentration before storage. The effect of α-tocopherol was unclear for the δ-lactones. The results indicate that most of the γ-lactones are produced by oxidation during storage but that the other lactones are also generated by other processes as well.     

Effect of temperature on evolution of free amino acid and biogenic amine contents during storage of Azeitão cheese

A study on the evolution of free amino acids and biogenic amines in Azeitão cheese during 4 weeks at different temperatures of storage (4 and 25°C) was performed. Free amino acids and biogenic amines were determined by RP-HPLC with visible detection, following extraction from the cheese and derivatization with dabsyl chloride. The method presented a linear relation between peak area and concentration from 2–200 mg/l. The detection limit value was less than 1.5 mg/l. The average repeatability was less than 4%. The major free amino acids were proline, valine, isoleucine and leucine and the major amines were tyramine, cadaverine and histamine. Room temperature (25°C) promoted a significant increase of the contents of valine, leucine, tyramine and putrescine, expressed as g/kg of dry matter. These two free amino acids and two biogenic amines may serve as indicators of temperatures changes in ripened cheese.     

Effect of rosemary extract, chitosan and α-tocopherol on lipid oxidation and colour stability during frozen storage of beef burgers

The effect of rosemary extract, chitosan and α-tocopherol, added individually or in combination, on lipid oxidation and colour stability of frozen (−18 °C) beef burgers stored for 180 days was investigated. The burgers’ lipid oxidation and appearance were evaluated through measurement of primary (conjugated dienes and peroxide value) and secondary (malondialdehyde) oxidation products, together with visual assessment and instrumental measurement of colour. Chitosan alone and in combination with either rosemary or α-tocopherol had the best antioxidative effect (P ? 0.05) compared to individual use of rosemary or α-tocopherol, while the best results were obtained with the combination of chitosan and rosemary. The differences of antioxidative effects, however, between individual use of rosemary or α-tocopherol as compared to the controls were also significant (P ? 0.05). Chitosan added individually or in combination with either rosemary or α-tocopherol had also a noteworthy effect on the burgers’ appearance as it contributed to red colour retention for a much longer period (P ? 0.05) compared all other treatments and the controls. In conclusion, the best antioxidative effects were obtained with the combination of chitosan and rosemary extract.