Effect of processing and storage on neutral lipids of buffalo meat

Three muscles viz. Triceps brachii (TB), Longissimus dorsi (LD) and Biceps femoris (BF) from different anatomical locations of adult male buffaloes were stored after broiling and pressure cooking under refrigerated (4°C) condition for 3, 6, 9 days and 30, 60, 90 days under frozen (-10°C) storage. At the end of each storage interval they were analysed for total lipids, cholesterol contents and glyceride fractions i.e. monoglycerides (MG), diglycerides (DG), and triglycerides (TG). Muscles differed significantly in total lipids as well as contents of all glyceride fractions. Muscle LD had significantly higher total lipid content than TB and BF. Muscles differed significantly in their esterfied cholesterol (EC) contents. Heat processing increased total lipids, cholesterol, MG, DG and TG contents of all the buffalo muscles studied. Total cholesterol contents remained unchanged during refrigerated and frozen storage. However, EC, MG, DG and TG contents declined during storage. The influence of anatomical locations on fatty acid composition of neutral lipids was observed. The ratio of unsaturated to saturated fatty acids increased due to cooking. A gradual decrease in mono- and polyunsaturated fatty acids was recorded during refrigerated and frozen storage.     

Changes of lipoprotein phospholipids during rapeseed processing

During rapeseed processing about 0.4—0.8 % lipids are liberated from their bound form and extracted into expeller-pressed or extracted oils, increasing thus the yield in an oil processing plant, compared with the yield predicted on the basis of Soxhlet extraction [1]. If the liberated lipids originate from lipoproteins denatured during processing, they would contain high percentage of phospholipids. Therefore, we have studied changes of phospholipids during rapeseed processing.     

Stability of fat during irradiation and subsequent storage of irradiated buffalo meat

Summary Buffalo meat steaks were irradiated with gamma-rays in doses of 0,550 and 1100 krad and stored at 2±1 °C. The changes in lipids extracted from the steaks were investigated. Peroxides and carbonyl compunds accumulated during irradiation and subsequent storage of the irradiated meat. Oxidation products were higher if irradiation was carried out with 1100 krad than with 550 krad. Soaking of the steaks in butylated hydroxy toluene (BHT) and sodium pyrophosphate before irradiation markedly reduced the amount of peroxides and carbonyl compounds formed during irradiation and storage. Treatment of meat muscle 800 V for 45 s reduced weeping but increased slightly the rate of autoxidation of lipids. The browning reaction was slow during cold storage of irradiated meat but increased upon storage of extracted lipids at room temperature.

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Stabilität von Fett im Verlauf der Bestrahlung und Lagerung von bestrahltem Büffelfleisch

Zusammenfassung Steaks aus Büffelfleisch wurden einer Gammabestrahlung von 0,550–1100 krad ausgesetzt und anschließend bei 2±1 °C gelagert; danach wurden die Veränderungen in der Fettfraktion gemessen. Peroxyde und Carbonylverbindungen sind bei der Bestrahlung und der Lagerung des bestrahlten Fleisches angereichert worden. Bei einer Dosis von 1100 krad war der Anteil der Oxydationsprodukte höher als bei 550 krad. Eintauchen der Steaks in BHT oder Pyrophosphat vor der Bestrahlung bewirkte eine deutliche Reduzierung der Peroxyde und Carbonylverbindungen. Eine elektrische Behandlung des Fleischmuskels (800 V 45 s) verringerte den Feuchtigkeitsaustritt, erhöhte jedoch etwas die Autoxydation der Fette. Die Bräunungsreaktion war schwach im Verlauf der Kaltlagerung des Fleisches, stieg jedoch an bei Lagerung der extrahierten Fette bei Zimmertemperatur.

     

苏州传统腌腊肉加工贮藏中的品质变化

以苏州地区家庭自制腊肉为原料,对其加工和贮藏过程中主要理化指标和黄曲霉毒素B1进行了测定。结果表明,腊肉生产和贮藏过程中,水分含量逐渐下降,而腊肉的挥发性盐基态氮含量、酸价、过氧化值、TBA值等均呈上升的趋势,90d时,黄曲霉毒素B1为0.031μg/kg。家庭自制腊肉加工贮藏60d后,存在一定安全隐患。     

Changes in lightness of porcine lean meat batters during processing

The pattern of changes of lightness (L^*) for porcine lean meat batters (PLMBs) with time was divided in two phases: chopping process (Phase 1) resulting in a sharp increase of L^*, and the subsequent storage of the batters for 24 h at 15°C (Phase 2). During Phase 2, L^*-values decreased with time approximating a plateau. The subjects of study were effects on the course of L^* of: (1) added sodium chloride and phosphate in Phase 2, (2) the fate of air bubbles embedded in the batters in Phases 1 and 2, and (3) changes in light absorption by the pigment myoglobin in Phase 2.

(1) Sodium chloride and phosphate appeared to have very little impact on the changes in L^* during storage of the PLMBs at 15°C, although microstructural changes were distinct.

(2) Continuous entrapment of air during the chopping process had a major effect on the increase of L^* in Phase 1, air bubbles being scattering elements in the PLMB. Disproportionation caused a decrease in the number of small air bubbles, resulting in a decrease of L^* during the early stage of Phase 2 (about 35 min), immediately after the chopping stage was finished.

(3) Strong evidence was obtained that shifts in the absorption traits of pigments (red nitric oxide myoglobin was formed at the cost of grey met-myoglobin) during the period from 1 to 5 h, caused a marked decrease in the pattern of L^* during Phase 2.     

Changes in carotenoids during processing and storage of pumpkin puree

Changes in the contents of carotenoids and their true retentions (% TR) during the production of puree of Cucurbita moschata ‘Menina Brasileira’ and of Cucurbita maxima ‘Exposição’ pumpkins and the stability of such compounds during 180 days of storage were monitored by liquid chromatography coupled with a photodiode array detector. Cooking caused higher losses than commercial sterilisation. High losses of xanthophylls such as lutein and violaxanthin were noted during processing and storage of pumpkin puree. Such losses show the low stability of these compounds. The major carotenoids, pro-vitamin A carotenes, namely, α-carotene and all-trans-β-carotene for C. moschata ‘Menina Brasileira’ and all-trans-β-carotene for C. maxima ‘Exposição’ obtained high retentions (>75%) after processing. A slight degree of isomerisation of β-carotene was noted in the puree samples, but with low concentrations of cis-isomers. Storage for 180 days did not significantly affect (P ? 0.05) the concentrations of these carotenoids.     

Role of triglycerides and phospholipids on development of rancidity in model meat systems during frozen storage

The effect of triglycerides, phospholipids and total lipids on development of rancidity during frozen storage at ?18° C for 8 months was studied using lipid-free muscle fibres in combination with added triglycerides, phospholipids and total lipids. Results showed that added phospholipids greatly increased TBA values. Oxidation took place in two stages. Phospholipids were the first to oxidise, with their rate of oxidation decreasing with time. Oxidation of the triglycerides began only after a prolonged induction period. Results demonstrated that both triglycerides and phospholipids contribute to development of rancidity, although phospholipids make the greatest contribution. The influence of triglycerides on the development of rancidity was shown to depend upon the degree of unsaturation and the length of time in frozen storage. The relationship between oxidation of the polyunsaturated fatty acids (PUFAS) of the phospholipids and development of rancidity was confirmed.     

Effect of natural antioxidants and vacuum packaging on the quality of buffalo meat nuggets during refrigerated storage

Buffalo meat nuggets (BMN) were incorporated with 500 ppm sodium ascorbate, 10 ppm -tocopherol acetate and 0.5% sodium tripolyphosphate while processing. There were three experimental groups of BMN, namely control aerobic packaged (CAP), treated aerobic packaged (TAP) and treated vacuum packaged (TVP), refrigerated and stored at 4 °C. It was observed that the treated samples (TAP and TVP) had significantly (p < 0.05) higher pH, W-B shear force, moisture and protein contents, sensory attributes and lower free fatty acids content in comparison to CAP samples. Vacuum packed nuggets (TVP) had significantly (p < 0.05) lower free fatty acid content, higher lactobacilli and total anaerobe counts and markedly higher scores for flavour and overall palatability, even at the 25th day of storage. Product quality reduced as storage time increased. Use of natural antioxidants and vacuum packaging extended the shelf life of BMN from 10 to 30 days under refrigerated storage.     

Effect of age and gender on the processing characteristics of buffalo meat

Comparison of processing characteristics of meat from young male, spent male and spent female buffaloes was made to find the suitability of the meat for developing ready to eat meat products. Intensively reared young male buffalo meat showed higher moisture, collagen solubility, sarcomere length, myofibrillar fragmentation index and water holding capacity than meat from the other animals. A higher pH, total meat pigments, salt soluble protein, emulsifying capacity and lower collagen solubility were observed in spent male buffalo meat. Spent female buffalo meat had higher fat, total collagen, muscle fibre diameter and shear force value. Sensory evaluation of pressure cooked meat chunks indicated a marked toughness in spent male and female buffalo meat samples. These results suggest that young male buffalo meat is more suitable for processing in chunks and spent male and female buffalo meat is more suitable for processing in smaller particles.     

Problems during processing and storage of meat in cans. II. Chemical changes in canned meat with long storage time (author's transl)]

By sensory analysis and according to results of objective chemical investigations meat cans sterilized at 120 degrees C for long storage times were at best evaluated, if they were processed after the 4th and 7th day after slaughter. At first the 4th day; after 2 days the 7th day were preferred. 2. For comparison meat cans with long storage time of 5 and 9 years were analyzed in the same manner. In taste these were empty, strawy, and partly bitter. Frozen meat which was processed according to old procedures (long stored without any shock freezing), was regarded, extremely unagrellable. The attributs were adstringend and soapy. 3. Gelfiltration of diffusates showed a separation in 2 main peaks. The first from fractions 90--130 had a typical aroma of a heated meat, after hydrolysis glucose was detected as main sugar component. The 2th peak from fractions 170--230 tasted more sweet with parfumlike odor, after hydrolysis ribose was detected besides other substances stained by anisidine phthalate. 4. During storage substances of peak 1 were reduced in contrast to peak 2 substances. The latter seemed to be responsible for the aroma and taste at beginning of eating, but no fixation at the tongue could be observed in contrast to the substances of the peak 1. 5. Staining of separated peptides--by electrochromatography--with ninydrin received from the diffusates of the meat cans showed some brown coloured peptides, which disappeared during storage. This was in good correlation with the results of sensory analysis.     

Changes of intramuscular phospholipids and free fatty acids during the processing of Nanjing dry-cured duck

In this study, changes of intramuscular phospholipids and free fatty acids were tracked during the processing of Nanjing dry-cured duck. Phospholipids were identified and quantified by high performance liquid chromatography combined with UV and evaporative light scattering detectors. The types and quantities of free fatty acids and fatty acids derived from phospholipids were analyzed by capillary gas chromatography. The results showed that raw duck meat had high quantities of phosphatidylethanolamine, and phosphatidylcholine (37.95% and 54.07% of total phospholipids, respectively), which contained high percentages of polysaturated fatty acids. The percentages of total phospholipids, phosphatidylethanolamine, and phosphatidylcholine decreased during processing, with a concomitant increase in quantities of free fatty acids. The lipolysis of phospholipids, especially phosphatidylethanolamine is the main contributor to the increase of free fatty acids.     

Changes in the levels of 2-phenylethylamine in cheese and chocolate during processing and storage

Amines from cheese and chocolate were extracted with solvent and separated from non-basic material on an ion-exchange column. The amines were reacted with trifluoroacetic anhydride after the addition of aminotetrahydronaphthalene as an internal standard. The derivatives were analysed on a SCOT column by gas chromatography. The levels of phenylethylamine increased in cocoa beans during fermentation and roasting. Some samples of cheese contained phenylethylamine. whereas others prepared aseptically did not.     

雅安罐罐肉加工与贮藏过程中肌肉蛋白质的变化

为了探明雅安罐罐肉蛋白质的变化规律,以不同加工与贮藏阶段的罐罐肉为对象,采用常规理化检测方法以及SDS-PAGE电泳法分析其蛋白质的变化情况。结果显示:罐罐肉在油炸结束后蛋白酶活性为零;非蛋白氮(NPN)与游离氨基酸(FAA)含量在油炸结束时显著上升(P<0.01),FAA达到最大值(219.2 mg/100 g),在贮存的前期与中期缓慢下降,后期又有所回升,NPN达到最高值(0.616%);肌浆蛋白和肌原纤维蛋白经过高温油炸,蛋白质含量(干基)下降为4.18 mg/g和4.70 mg/g,大于66ku的蛋白质条带完全消失,积累大量小于16ku的条带,肌浆蛋白贮藏后期还出现了51ku和42ku的新条带。研究结果表明,雅安罐罐肉蛋白质的变化主要发生在油炸阶段,贮藏过程中的变化非常缓慢。     

Changes in the fatty acid composition of dietetic ready-to-cook chicken meat products during frozen storage

A study was made on the fatty acid composition of dietetic ready-to-cook products of boneless chicken legs or breasts prepared by curing using several curing mixtures during frozen storage. Leg muscles were found to be richer in unsaturated fatty acids than breast muscles, substantial differences having been found in the contents of palmitoleic and linolenic acids. During frozen storage, the contents of unsaturated fatty acids were reduced, especially intensively in the leg muscle ready-to-cook products. The fastest changes occurred in linolenic and linolic acids and partly in palmitic acid. The level of oleic acid remained substantially unchanged throughout the storage period. Irrespective of the changes found, the ratio of unsaturated and saturated fatty acids in all the groups studied remained greater than 1 for both types of meat. The application of citrate in the curing mixture had a favourable effect on the changes, in that a minimum alteration in the contents of unsaturated fatty acids was achieved.     

Changes in milk fat phospholipids during lactation

Changes in lipid composition were studied in milk obtained on postpartum d 3 (colostrum), 7, 42, and 180 from 12 Holstein cows. Triglycerides, 96 to 97% of total lipids, were relatively constant during lactation. Phospholipids and cholesterol declined with advancing lactation. Concentrations of the fatty acids synthesized within the mammary gland, C10:0 to C16:0, increased about 50% from 7 to 42 d of lactation. During this period, compensatory decreases were observed in C18:1. The phospholipids were separated into five major classes: sphingomyelin, phosphatidyl choline, serine, inositol, and ethanolamine for fatty acid analysis. The changes that occurred in milk total fatty acids were reflected in phosphatidyl phospholipid fatty acid composition: an increase in medium-chain fatty acids and a decrease in polyunsaturated fatty acids of 18, 20, and 22 carbon atom chain length as lactation progressed. These changes are consistent with the theory that milk phospholipids are synthesized de novo entirely in the mammary gland.     

Effect of freezing, thawing and frozen storage on physico-chemical and sensory characteristics of buffalo meat

A study was conducted on some physico-chemical and sensory characteristics of buffalo meat frozen by plate and blast freezing and stored at −15 ± 3°C for a period of 3 months. A marginal increase in pH values and drip losses were observed during the storage period. Drip losses were less in blast frozen samples. WHC, cooking losses thermal shrinkage and WB Shear values indicated inconsistent results, during storage. Similar observations were recorded with regard to tyrosine and TBA values. No significant differences in the physico-chemical characteristics were observed between meat cuts and minced meat. Plate frozen meat samples scored higher for texture, juiciness and aroma. Both the plate and blast frozen meat samples, however, were similar in overall quality according to taste panel results.     

带骨兔肉脯的加工与贮藏

将兔骨制成食用骨粉,兔肉斩成肉糜,制成带骨兔肉脯。采用4因素3水平正交试验筛选出了带骨兔肉脯较优配方。并进行了带骨兔肉脯的辐射处理等贮藏试验。     

Antioxidant consumption and development of oxidation during ageing of buffalo meat produced in Argentina

Buffalo meat production is increasing in Argentina. Information on meat quality and nutritional value will be useful in marketing. This work describes the oxidative stability of the Longissimus dorsi (LD) in relation to consumption of antioxidant vitamins, fatty acid composition and color deterioration during ageing. Vitamins levels found in fresh beef were 4.22±0.93; 0.24±0.05 and 0.25±0.06μg/g for α- and γ-tocopherol, and β-carotene, respectively. Vitamin loss was almost 90% throughout an ageing period of 25 days at 2°C. Concomitantly, TBARS levels increased from 0.076±0.018 to 0.14 6±0.032mg MDA/kg beef. Hexanal and pentanal levels were low and no correlations with oxidation were detected (P>0.05). The predominant color changes in aged beef were reduced redness and yellowness with an increase in lightness (P<0.05). Vitamin levels and TBARS were used to develop a prediction equation for post-mortem aging.     

Effect of cooking and storage on lipid oxidation and development of cholesterol oxidation products in water buffalo meat

Buffalo meat was subjected to two cooking methods viz. broiling and pressure cooking and two storage procedures viz. refrigerated (4 °C) storage for six days and frozen (-10 °C) storage for 90 days. Changes in lipid oxidation and development of cholesterol oxidation products were studied in raw as well as cooked meat samples. Total lipid, phospholipid, cholesterol, free fatty acid, glycolipid and glyceride contents increased significantly on cooking of meat but did not show any significant changes during either refrigerated or frozen storage except for free fatty acid content which showed an increase. The TBA values also increased during storage but not to the extent of indicating rancidity. Cholesterol oxidation products separated by thin layer chromatography were: cholestanetriol, 7-α-hydroxycholesterol, 19-hydroxycholesterol, 7-ketocholesterol, cholesterol-α-epoxide, cholesterol-β-epoxide and an unidentified fraction. All these fractions, except for the unidentified fraction, increased on cooking and storage. The cholesterol-β-epoxide fraction was resistant to changes. Changes in broiled meat were more pronounced compared to pressure cooked meat. Frozen storage did not prevent the development of cholesterol oxidation products in buffalo meat.     

Comparative study of buffalo meat and beef

The aim of the experiment described in this paper was to compare buffalo and cattle breeds for meat production. Bulls and steers of both species were compared. Buffaloes and cattle were of comparable conformation on a weight to length ratio basis when slaughtered at the same liveweight. Apart from sex and weight effects, species did affect the conformation and growth of live animals, the largest differences between species being evident in the younger animals. As regards slaughter characteristics, although differences in carcass yield were slight between species, systematic differences appeared, with a higher head and skin weight for buffaloes. A higher proportion of fat was noted in the 11th rib joint of buffaloes than of cattle at the lighter weights but the difference between species lessened with slaughter weight. As far as meat quality is concerned, two major effects of species on muscle pH (24 h post slaughter) and the shear strength of raw muscle were noted. Buffaloes, which had a lower muscle pH than cattle, displayed a significantly smaller amount of collagen in the muscles studied, but the species did not differ significantly in the degree of intramuscular collagen crosslinking.