Physical, Sensory and Microbiological Characteristics of Lamb Retail Cuts Vacuum Packaged in High Oxygen-Barrier Film

Lamb chops and steaks from fresh (F) or vacuum packaged (VP) racks, loins and legs were packaged in polyvinyl chloride (PVC) film or vacuum packaged in high oxygen-barrier (HOB) film. Use of previously vacuum packaged (PVP) cuts did not affect overall appearance of rib or loin chops during subsequent retail display but HOB film-packaged leg steaks from PVP cuts had lower overall appearance scores than did leg steaks from F cuts. Prior VP storage negatively affected flavor desirability and odor at the conclusion of retail display (4 days in PVC or 10 or 15 days in HOB film). Pseudomonas spp. were a dominant part of the microflora of PVC-wrapped chops while L. cellobiosus was a dominant part of the microflora of HOB-wrapped chops.     

Fynbo Cheese NaCl and KCl Changes during Ripening

In a model study we assumed that the cheese is a homogeneous solid with nonuniform initial concentration distributions, cheese surfaces are rendered impermeable after brining, and the generalized Fick's law form is valid for expressing the diffusive fluxes of solutes. NaCl and KCl concentrations at selected positions during distribution in Fynbo cheese kept at 12°C, after salting 10 hr in a brine of 100 g NaCl/L and 100 g KCl/L at the same temperature, were determined experimentally and compared with predicted values with the model at different storage times up to 30 days. Homogeneous distribution of solutes was reached at 20 days ripening, as predicted by the model and verified experimentally.     

Culture Effect on Ripening Characteristics and Rheological Behavior of Cheddar Cheese

Six defined strains of bacteriophage-insensitive Streptococcus cremoris, grown in whey-based starter media, were used over a period of 10 months to produce more than 2 million kg of Cheddar cheese on continuous cheesemaking equipment. Flavor development in this cheese was less than that in cheese made with conventional bulk starter. Proteolysis in the trichloracetic acid (TCA) soluble cheese fraction was less in cheese manufactured using S. cremoris compared to conventional bulk starter. Rheological properties were studied and the force-compression curves related to the age, composition and pH of the cheese. Pattern recognition techniques were used to analyze the multivariate data. The texture was affected by the mechanical process, moisture content and yield point of the cheese. Casein proteolysis, age, culture type and firmness were the most discriminating variables affecting maturity.     

Microbiological, Chemical, and Sensory Changes in Irradiated Pica De Gallo

The effects of gamma processing (1 kGy) and refrigerated storage (2°C) on microbiological, sensory, and chemical quality of pico de gullo was studied. Color, flavor, texture, odor, and heat sensory attributes were not affected by radiation treatment. The treatment decreased populations of aerobic mesophilic, heterofermentative, and total lactic microflora during storage. L-ascorbic acid content declined 50% in response to gamma processing, but levels were similar in irradiated and nonirradiated samples after 6 wk. Pectin solubility was affected by radiation treatment. Gamma processing caused a reduction in pectin degree of esterification, and conversion of chelator soluble to dilute alkali soluble and nonextractable pectins.     

Influence of Manufacturing and Ripening Conditions on the Survival of Enterobacteriaceae in Manchego Cheese

The effects of cooking temperature, time and temperature of brine-salting, and temperature of ripening on the behavior of Enterobacteriaceae in Manchego cheese were studied. Fifty lots of cheese from raw ewe's milk manufactured and ripened under different conditions were investigated throughout a 60-day ripening period. Differences in pH values due to temperature-dependent whey retention accounted for the effect of cooking temperature on coliform and fecal coliform counts. Temperature of brine-salting had no effect on Enterobacteriaceae counts, but a significant effect of salting time on Enterobacteriaceae and fecal coliform counts was detected. Ripening temperature was the manufacturing variable with greatest influence (P<.01) on Enterobacteriaceae and coliform counts during the whole curing period.     

Reduction of Sodium Chloride in Cheddar Cheese: Effect on Sensory,Microbiological, and Chemical Properties

AbsractCheddar cheese containing selected levels of added NaCl ranging from 0 to 1.44% was evaluated for various chemical, microbiological, and sensory properties over a 7-mo ripening period. Cheese with the least NaCl showed an increase in proteolysis and water activity. Cheese with less salt supported higher lactic acid bacteria populations. Trained panel evaluation of the experimental cheese with reduced levels of NaCl showed an increase in adhesiveness, cohesiveness, acidity, bitterness, unpleasant aftertaste, and a concomitant decrease in firmness and saltiness. Consumers were unable to detect flavor and texture differences in cheese containing 1.44 and 1.12% NaCl. Although consumers noted a difference between 1.12 and .73% NaCl, cheese with .73% salt received acceptable overall desirability ratings.     

Physical, Chemical and Sensory Changes in Irradiated Fresh Pork Packaged in Modified Atmosphere

The effects of irradiation dose (0, 0.5 and 1.0 kGy), headspace oxygen (0, 10 and 20% O₂, balance nitrogen) and storage temperature (5, 15 and 25°C) on the physical, chemical and sensory changes in fresh pork were studied using factorial design experiments. Irradiation in the absence of oxygen extended the sensory shelf life of pork from 9 to 26 days at 5°C and from & lt; 2 to 2 days at 25°C. Oxygen in the package headspace combined with irradiation adversely affected physical, chemical and sensory characteristics of the end product.     

Edam牦牛干酪成熟过程中品质变化及蛋白质降解

为研究Edam牦牛半硬质干酪成熟机理,分别测定成熟0、20、40、60、80 d Edam牦牛干酪的感官、理化、物性、蛋白质和脂肪分解指标,采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和傅里叶变换红外光谱等方法研究酪蛋白降解情况,通过Pearson相关性分析成熟时间与各指标间的相关性。结果表明：随着成熟时间延长,感官评分先下降后上升;水分含量、pH值下降;亮度值（L*）下降,红度值（a*）和黄度值（b*）值上升;硬度、弹性、胶黏性均上升,凝聚性逐渐下降;储能模量和损耗模量升高,损耗角正切值始终小于1;成熟时间与总氮含量、pH 4.6和12%三氯乙酸条件下干酪中可溶性氮含量等呈极显著正相关（P<0.01）;脂肪含量先升高后降低,游离脂肪酸含量和硫代巴比妥酸值逐渐增加。酪蛋白（casein,CN）降解研究结果表明：αs1-CN、αs2-CN、β-CN及κ-CN均随成熟时间延长而不断降解,成熟80 d时大分子蛋白降解明显;成熟过程中β-折叠、α-螺旋逐渐向无规卷曲转化;成熟时间与羰基含量、表面疏水性呈极显著正相关（P<0.01）,与总巯基含量呈显著负相关（P<0.05）。     

真空包装冷却鹿肉贮藏过程中的菌相变化

利用聚合酶链式反应-变性梯度凝胶电泳方法研究真空包装的冷却鹿肉贮藏过程中的菌相变化。将冷却鹿肉真空包装贮藏于0~2℃条件下,每隔5 d取出,利用细菌试剂盒提取细菌DNA,进行聚合酶链式反应-变性梯度凝胶电泳分析,同时对16S rDNA V3区的DGGE图谱进行割胶测序,检测到贮藏末期主要是苏黎世克罗诺杆菌、斯氏普罗威登斯菌,棕色类香味菌,乳酸发酵类梭菌等成为优势腐败菌。     

Mozzarella干酪成熟过程中菌相变化规律的研究

为了研究Mozzarella干酪成熟过程中发酵剂菌种对干酪成熟的影响,本试验制作了模拟干酪,并以此为试验模型,分析了全脂Mozzarella干酪成熟过程中菌群的变化规律。结果表明:发酵剂乳酸菌是Mozzarella干酪成熟过程中的主要菌群,而且球菌在干酪成熟过程中占绝对优势;NSLAB对Mozzarella干酪成熟的作用不大。由于采用了真空包装,Mozzarella干酪中的杂菌数始终保持在很低的水平〔大肠菌群≤60MPN/100g,酵母霉菌≤45lg(cfu/g)〕,并且对干酪的成熟无影响。在Mozzarella干酪成熟过程中,乳糖含量逐渐下降,随着乳酸菌的自溶,使LDH增加,对干酪后期的成熟产生积极影响。     

Development of Meat Snack Dips: Chemical, Physical, Microbiological and Sensory Characteristics

Snack dips containing 50% ham, 26% bacon or 28% pepperoni in combination with sour cream, unflavored yogurt and tofu were developed. The developmental phases of the study were discussed in relation to ingredient and meat flavor selection, formulation and sensory evaluation. Microbiological, chemical and physical analyses of the new products indicated that the meat-containing snack dips were stable and safe under storage conditions simulating wholesale (3 wk 2-4°C), retail (10 days, 5°C, household (10 days, 8-10°C) and longer-than-normal temperature abuse (12 and 24 hr, 24-25°C).     

Probiotic Cheddar Cheese: Influence of Ripening Temperatures on Proteolysis and Sensory Characteristics of Cheddar Cheeses

ABSTRACT:  Bifidobacterium longum 1941, B. animalis subsp. lactis LAFTI^® B94, Lactobacillus casei 279, Lb. casei LAFTI L26, Lb. acidophilus 4962, or Lb. acidophilus LAFTI L10 were used as an adjunct in the production of Cheddar cheeses, which were ripened at 4 and 8 °C for 24 wk. Effects of ripening temperatures and probiotic adjuncts on proteolysis and sensory evaluation of the cheeses were examined. Higher ripening temperature increased the level of proteolysis in the cheeses. Product of proteolysis and organic acids released during ripening were shown to be important for the flavor of Cheddar cheeses. There were positive and significant correlations between the levels of soluble nitrogen, lactic, acetic, and butyric acids, percentage hydrolysis of α_s1-CN and β-CN to the scores of cheddary flavor ( P < 0.05). Scores for sour-acid and vinegary flavors were higher in cheeses with the addition of Bifidobacterium sp. or Lb. casei 279 ripened at 8 °C. The scores were positively and significantly correlated to the level of lactic, acetic, and free amino acids in the cheeses ( P < 0.05). The results show that both 4 and 8 °C have potential for use in the ripening of probiotic Cheddar cheeses.     

Viscoelastic Property Changes in Cheddar Cheese During Ripening

The rheological properties of pasteurized and raw milk Cheddar cheese were studied using oscillatory dynamic measurements, and a specially designed rheometer fixture that prevented specimen slippage. Dynamic measurements within the linear viscoelastic range were made throughout ripening. Within-cheese changes, as related to ripening time, as well as between-cheese-type differences in G’ and G” were observed. Differences in rheological characteristics were attributed to proteolytic activities in Cheddar cheese during ripening. Specific peptide profiles associated with proteolysis during ripening may affect cheese rheological properties.     

Changes of Mineral Concentrations in Serra Cheese during Ripening and Throughout the Cheesemaking Season

Seasonal changes of the ash content and mineral concentrations in Serra cheese were studied over a typical 35-day ripening period. Statistically significant differences (at the 5% level) exist between the ash content and the concentrations of Na, K, Ca, P, Mg and Zn in cheeses during ripening. The highest concentrations of Na was obtained in cheese ripened for 7 days, whereas the concentrations of K, Ca, P, Ng and Zn decreased significantly during ripening. For 35-day-old cheeses, concentrations of Na, K and Cu were lowest and concentration of P was highest for cheeses manufactured in May. The concentration of Ca was lowest for cheeses manufactured in February. On average, the most concentrated minerals (in g kg^-1 of total solids, TS) in 35-day-old Serra cheese were Na (18·56), Ca (9·70) and P (7·92) and, at a lower level, K (1·70) and Mg (0·96). Only trace levels (in mg kg_TS^-1) of Zn (94·33), Cu (2·26) and Mn (1·25) were detected. A high mineral nutrition quality was thus ascribed to 35-day-old Serra cheese based on the average nutritional densities: 4·8 for Ca, 4·0 for P, 1·1 for Mg, 3·4 for Na, 2·4 for Zn, 0·4 for Cu, 0·2 for Mn and 0·2 for K. © 1997 SCI     

不同方法促熟干酪成熟期间微生物及氨基酸研究

以0、15、30、45、60、75、90 d促熟干酪中主要微生物（乳杆菌、乳球菌、肠球菌、微球菌）和游离氨
基酸含量为指标,研究添加复合处理发酵剂和中性蛋白酶促熟干酪成熟过程对游离氨基酸和微生物菌落数的影响。
结果表明,添加处理发酵剂和中性蛋白酶可增加干酪中游离氨基酸含量,添加处理发酵剂可不同程度降低干酪中微
生物菌落数,添加中性蛋白酶对干酪成熟过程中微生物影响不明显（P＞0.05）。     

Effect of Freezing and Frozen Storage on Chemical and Microbiological Characteristics in Sheep Milk Cheese

ABSTRACT: Most chemical components and water activity of an the Los Pedroches' brand ewes' milk cheese were not altered by frozen storage. Lactic acid concentration and pH were significantly different (p < 0.05) in control cheeses and those kept in frozen storage for 3 and 6 months from those stored for 9 months. Proteolysis continued slowly during frozen storage, with significantly higher rates of non protein nitrogen and amino acid nitrogen (p < 0.05) present at the end of the storage period. Counts of microorganisms, except for enterococci, tended to decrease during frozen storage. Freezing rates did not affect the chemical and microbiological characteristics studied.     

Microbiological and Chemical Properties of Cheese Helva Produced in Turkey

In this study, the microbiological and chemical properties of Cheese helva, one of the traditional cheeses varieties produced in Turkey, was studied. This cheese is called Cheese helva since it is produced from wheat flour and milk cream. Samples were randomly collected from different villages in the Erzurum province of Turkey. The average of total aerobic mesophilic bacteria (TAMB), yeast and mould, yeast, lactic acid bacteria (LAB), proteolytic bacteria, and lipolytic bacteria were determined 4.9 × 10⁷, 6.4 × 10⁴, 3.5 × 10³, 7.6 × 10⁶, 4.6 × 10³, and 8.6 × 10³ cfu/g, respectively. 44.44% of the Cheese helva samples had no coliform; the samples that were positive for coliform showed an average of 5.1 × 10³ cfu/g. Staphylococcus aureus was found < 10 cfu/g in analyzed samples. The Cheese helva was characterized by dry matter as 84.32 kg/100 kg cheese, fat as 37.44 kg/100 kg cheese, protein as 13.75 kg/100 kg cheese, NaCI as 0.58 kg/100 kg cheese, titratable acidity as 0.210%, pH as 5.30, ash as 1.49 kg/100 kg cheese, and carbohydrate as 38.56 kg/100 kg cheese. Cheese helva was found to have a high variation based on chemical composition. The microbiological tests revealed that there were high amounts of total bacteria, yeast and molds, molds, lactic acid bacteria, lipolytic bacteria, proteolytic bacteria, and coliforms.     

Chemical, Microbiological and Sensory Properties of Plain Nonfat Yogurt

Chemical and microbiological properties of plain nonfat yogurt were determined after 2, 6 and 12 days refrigerated storage. Sensory properties were determined after 6 days storage. Viable culture bacteria concentrations ranged from 140 to 8,000 × 10⁶/g and ratios of lactobacillus to streptococcus ranged from 0.18 to 15.4. Chemical criteria used to characterize products included: pH, titratable acidity, lactic and four other organic acids and lactose by HPLC, and 23 major volatile organic compounds by dynamic headspace analysis. Lactic acid concentrations ranged from 7.5 to 9.9 mg/g. Major flavor volatiles in all yogurts included: acetaldehyde, heptane, acetone, diacetyl, and benzothiazole. Untrained sensory panels showed differences for flavor, aroma and acceptability.