Effect of somatic cell count in goat milk on yield, sensory quality, and fatty acid profile of semisoft cheese

This study investigated the effect of somatic cell count (SCC) in goat milk on yield, free fatty acid (FFA) profile, and sensory quality of semisoft cheese. Sixty Alpine goats without evidence of clinical mastitis were assigned to 3 groups with milk SCC level of <500,000 (low), 500,000 to 1,000,000 (medium), and 1,000,000 to 1,500,000 (high) cells/mL. Thirty kilograms of goat milk with mean SCC levels of 410,000 (low), 770,000 (medium), and 1,250,000 (high) cells/mL was obtained for the manufacture of semisoft cheese for 2 consecutive weeks in 3 lactation stages. The composition of milk was analyzed and cheese yield was recorded on d 1. Cheese samples on d 1, 60, and 120 were analyzed for total sensory scores, flavor, and body and texture by a panel of 3 expert judges and were also analyzed for FFA. Results indicated that milk composition did not change when milk SCC varied from 214,000 to 1,450,000 cells/mL. Milk with higher SCC had a lower standard plate count, whereas coliform count and psychrotrophic bacteria count were not affected. However, milk components (fat, protein, lactose, casein, and total solids) among the 3 groups were similar. As a result, no significant differences in the yield of semisoft goat cheeses were detected. However, total sensory scores and body and texture scores for cheeses made from the high SCC milk were lower than those for cheeses made from the low and medium SCC milks. The difference in milk SCC levels also resulted in diverse changes in cheese texture (hardness, springiness, and so on) and FFA profiles. Individual and total FFA increased significantly during ripening, regardless the SCC levels. It is concluded that SCC in goat milk did not affect the yield of semisoft cheese but did result in inferior sensory quality of aged cheeses.     

Preparation and evaluation of pizza cheese made from blend of vetch–bovine milk

The objective of the study was to develop vetch–bovine milk (VBM) pizza cheese low in animal fat and its acceptability was determined through physico‐chemical, functional and sensory evaluations. Vetch (Lathyrus sativus) was detoxified by steeping in double its quantity of water for 8 h at 70 °C, changing the water seven times, draining and sun drying. Dried vetch was then treated with water at pH 4.0 at 90 °C for 60 min to deplete the beany flavour, then dried and milled into fine flour with Quadrumate Senior mill. The seed coat was separated as one of the mill fractions. Four types of VBM blends were prepared from vetch flour and bovine skimmed milk powder and were used to prepare cheese using 2.5% lactic acid bacterial culture of Streptococcus thermophillus and Streptococcus bulgaricus and rennet (0.15 mL L^?1, 1:40 ratio with water). The cheese was stored at 4 °C for 14 days and used as topping over the pizza shell. Physico‐chemical analyses, such as moisture, total solids, lactose, ash, fat, titratable acidity and pH, and sensory evaluations of both cheese and pizza were carried out at 0‐, 7‐ and 14‐day intervals. The stretchability and meltability of cheese increased significantly (P < 0.05) during storage. Commercial Mozzarella cheese was taken as a control. The results of this study suggested that VBM blend at the ratio of 12.5:87.5 (vetch flour:bovine milk powder) could be utilised to prepare a cheese of desirable characteristics for pizza topping.     

Agar-immobilized basil–lactic acid bacteria bioproducts as goat milk taste-masking agents and natural preservatives for the production of unripened goat cheese

Goat milk cheeses have become popular recently; however, many consumers do not choose these products because they have specific sensory properties that are not acceptable to all consumers and the shelf life of the cheese is short. The concept of this work was to increase overall acceptability and shelf life of unripened goat milk cheese by using Ocimum basilicum and lactic acid bacteria (Lactobacillus plantarum LUHS135, Lactobacillus paracasei LUHS244, Pediococcus pentosaceus LUHS100, Pediococcus acidilactici LUHS29, and Lactobacillus brevis LUHS140) bioproducts (basil-LAB) immobilized in agar. A basil-LAB bioproduct could be a promising multifunctional ingredient for cheese manufacturing because it has a low pH, high LAB count, and high total phenolic compound content (after fermentation pH decreased by 25.4%, LAB count averaged 7.2 log₁₀ cfu/g, and total phenolic compound content increased by 30.9%). Use of different LAB in the preparation of basil-LAB bioproducts had a significant influence on cheese pH and hardness, and compared with cheese samples prepared with nonfermented basil, cheese samples prepared with basil-LAB bioproducts had, on average, higher pH (by 2.6%) and lower hardness (by 36.0%), similar to the control cheese (without basil). Overall acceptability of cheese was significantly influenced by the basil-LAB bioproduct immobilization process; in all cases, cheese samples prepared with fermented and immobilized basil-LAB bioproduct had better acceptability (5 points). After 120 h of storage, cheese samples prepared with basil-LAB bioproducts fermented with LUHS135, LUHS244 and LUHS140, no enterobacteria were found, and we detected strong negative and moderate negative correlations, respectively, of LAB count with enterobacteria count and yeast/mold count (r = ?0.7939 and r = ?0.4495, respectively). Finally, immobilization increased LAB viability in fresh goat milk cheese, which led to a reduction in enterobacteria and mold/yeast contamination during storage and an increase in overall acceptability compared with nonimmobilized basil-LAB. Therefore, basil-LAB bioproducts fermented with LUHS135, LUHS244, and LUHS140 strains can be recommended for preparing fresh goat milk cheese with extended shelf life and high acceptability.     

Use of high-pressure-treated milk for the production of reduced-fat cheese

Pasteurized (65°C, 30 min), pressurized (400 MPa, 22°C, 15 min) and pasteurized–pressurized milks were used for reduced-fat (approximately 32% of total solids) cheese production. Pressurization of milk increased the yield of reduced-fat cheese through an enhanced β-lactoglobulin and moisture retention. In addition, pressurisation of pasteurized skim milk improved its coagulation properties. The cheeses made from pasteurized–pressurized and pressurized milks showed a faster rate of protein breakdown than the cheese made from pasteurized milk, that might be mainly attributed to a higher level of residual rennet. Hardness of the experimental cheeses, as determined by both the sensory panel and instrumental analyses, decreased as the moisture content and proteolytic degradation of the cheese increased (pasteurized>pressurized>pasteurized–pressurized). In general terms, pressurization of reduced-fat milk prior to cheese-making improved cheese texture and thus accounted for a higher overall acceptability, except for the cheeses made from pasteurized–pressurized milk at 60 d of ripening, whose acceptability score was adversely affected by bitterness.     

Influence of microfiltration and adjunct culture on quality of Domiati cheese

The effects of microfiltration and pasteurization processes on proteolysis, lipolysis, and flavor development in Domiati cheese during 2 mo of pickling were studied. Cultures of starter lactic acid bacteria isolated from Egyptian dairy products were evaluated in experimental Domiati cheese for flavor development capabilities. In the first trial, raw skim milk was microfiltered and then the protein:fat ratio was standardized using pasteurized cream. Pasteurized milk with same protein:fat ratio was also used in the second trial. The chemical composition of cheeses seemed to be affected by milk treatment—microfiltration or pasteurization—rather than by the culture types. The moisture content was higher and the pH was lower in pasteurized milk cheeses than in microfiltered milk cheeses at d 1 of manufacture. Chemical composition of experimental cheeses was within the legal limits for Domiati cheese in Egypt. Proteolysis and lipolysis during cheese pickling were lower in microfiltered milk cheeses compared with pasteurized milk cheeses. Highly significant variations in free amino acids, free fatty acids, and sensory evaluation were found among the cultures used in Domiati cheesemaking. The cheese made using adjunct culture containing Lactobacillus delbrueckii ssp. lactis, Lactobacillus paracasei ssp. paracasei, Lactobacillus casei, Lactobacillus plantarum, and Enterococcus faecium received high scores in flavor acceptability. Cheeses made from microfiltered milk received a higher score in body and texture compared with cheeses made from pasteurized milk.     

Biochemical,microbial and sensory evaluation of white soft cheese made from cow and lupin milk

The aim of the present study was to evaluate some physicochemical, microbiological and sensory properties of fresh and matured (75 days) soft cheeses made with mixtures of cow milk and 0, 25, 50 and 75 mL/100 mL of lupin milk. A remarkable increase in cheese yield was observed with increasing the level of lupin milk to the mixture. Compared to cow milk cheese, the protein content was significantly (P ≤ 0.05) increased while ash was decreased with the increase in the level of lupin milk for both fresh and matured cheese. However, fat content, total solids and acidity were increased only for fresh cheese and decreased for mature one compared to that of cow milk. The pH showed significant (P ≤ 0.05) reduction when the levels of lupin milk increased for fresh cheese while for matured cheese it slightly decreased. The total bacterial count is within the range that naturally exists in milk containing foods. The others microorganisms such as fungi, mold, Escherichia coli, and Salmonella were not existed in both types of cheese. Regardless of cheese color, incorporation of lupin milk at low concentration (25 mL/100 mL) significantly (P ≤ 0.05) enhanced the taste, texture, flavor, and overall acceptability of both fresh and mature cheese.     

Utilization of microfiltration or lactoperoxidase system or both for manufacture of Cheddar cheese from raw milk

The objective of the present study was to determine if application of microfiltration (MF) or raw milk lactoperoxidase system (LP) could reduce the risk of foodborne illness from Escherichia coli in raw milk cheeses, without adversely affecting the overall sensory acceptability of the cheeses. Escherichia coli K12 was added to raw milk to study its survival as a non-pathogenic surrogate organism for pathogenic E. coli. Five replications of 6 treatments of Cheddar cheese were manufactured. The 6 treatments included cheeses made from pasteurized milk (PM), raw milk (RM), raw milk inoculated with E. coli K12 (RME), raw milk inoculated with E. coli K12 + LP activation (RMELP), raw milk inoculated with E. coli K12 + MF (MFE), and raw milk inoculated with E. coli K12 + MF + LP activation (MFELP). The population of E. coli K12 was enumerated in the cheese milks, in whey/curds during cheese manufacture, and in final Cheddar cheeses during ripening. Application of LP, MF, and a combination of MF and LP led to an average percentage reduction of E. coli K12 counts in cheese milk by 72, 88, and 96%, respectively. However, E. coli K12 populations significantly increased during the manufacture of Cheddar cheese for the reasons not related to contamination. The number of E. coli K12, however, decreased by 1.5 to 2 log cycles during 120 d of ripening, irrespective of the treatments. The results suggest that MF with or without LP significantly lowers E. coli count in raw milk. Hence, if reactivation of E. coli during cheese making could be prevented, MF with or without LP would be an effective technique for reducing the counts of E. coli in raw milk cheeses. The cheeses were also analyzed for proteolysis, starter and nonstarter lactic acid bacteria (NSLAB), and sensory characteristics during ripening. The concentration of pH 4.6 soluble nitrogen at 120 d was greater in PM cheese compared with the other treatments. The level of 12% trichloroacetic acid-soluble nitrogen at 120 d was greater in RM, RME, and RMELP cheeses compared with PM, MFE, and MFELP cheeses. This could be related to the fact that cheeses made from raw milk with or without LP (RM, RME, and RMELP) had greater levels of NSLAB compared with PM, MFE, and MFELP cheeses. Cheeses at 60 d, as evaluated by 8 trained panelists, did not differ in bitterness, pastiness, or curdiness attributes. Cheeses at 120 d showed no differences in acid-taste, bitterness, or curdiness attributes. Sensory analysis at 60 d showed that PM and MFELP cheeses had greater overall sensory acceptability than RM and RME cheeses. The overall sensory acceptability of the cheeses at 120 d showed that PM, MFE, and MFELP cheeses were more acceptable than RM and RME cheeses.     

Effect of milk centrifugation and incorporation of high-heat-treated centrifugate on the composition,texture, and ripening characteristics of Maasdam cheese

This study investigated the effect of centrifugation (9,000 × g, 50°C, flow rate = 1,000 L/h), as well as the incorporation of high-heat-treated (HHT) centrifugate into cheese milk on the composition, texture, and ripening characteristics of Maasdam cheese. Neither centrifugation nor incorporation of HHT centrifugate into cheese milk had a pronounced effect on the compositional parameters of any experimental cheeses, except for moisture and moisture in nonfat substance (MNFS) levels. Incorporation of HHT centrifugate at a rate of 6 to 10% of the total milk weight into centrifuged milk increased the level of denatured whey protein in the cheese milk and also increased the level of MNFS in the resultant cheese compared with cheeses made from centrifuged milk and control cheeses; moreover, cheese made from centrifuged milk had ～3% higher moisture content on average than control cheeses. Centrifugation of cheese milk reduced the somatic cell count by ～95% relative to the somatic cell count in raw milk. Neither centrifugation nor incorporation of HHT centrifugate into cheese milk had a significant effect on age-related changes in pH, lactate content, and levels of primary and secondary proteolysis. However, the value for hardness was significantly lower for cheeses made from milk containing HHT centrifugate than for other experimental cheese types. Overall, centrifugation appeared to have little effect on composition, texture, and ripening characteristics of Maasdam cheese. However, care should be taken when incorporating HHT centrifugate into cheese milk, because such practices can influence the level of moisture, MNFS, and texture (particularly hardness) of resultant cheeses. Such differences may have the potential to influence subsequent eye development characteristic, although no definitive trends were observed in the present study and further research on this is recommended.     

Fresh cheese from camel milk coagulated with Camifloc

Camel milk was processed into cheese using Camifloc and calcium chloride. Two types of cheeses were produced from camel milk, using Camifloc (CF cheese) and CaC_l2 in addition to Camifloc (CFCC cheese). The study revealed the usefulness of Camifloc in coagulation of camel milk. The time of coagulation was found to be about 2–3 h, and the yield of CFCC cheese was found to be higher than the CF cheese, while a shelf life of 4 days was obtained for both cheeses. Both cheeses showed nonsignificant variations in compositional content except for the percentages of protein and ash, which showed significant differences at P < 0.001 and P < 0.05. Sensory evaluation by taste panellists was conducted to determine the acceptability of cheeses during the storage periods. Differences were found between the CF cheese and the CFCC cheese in saltiness and overall acceptability, and higher mean scores were recorded for the CF cheese than the CFCC cheese. The study recommends the use of Camifloc in making cheese from camel milk; and if CaCl₂ is added, it can improve the cheese yield. However, we suggest that the rate of salting should be reduced, and further drying and storage of the cheese should be done.     

Effect of iron fortification on microstructural,textural, and sensory characteristics of caprine milk Cheddar cheeses under different storage treatments

In this study, we manufactured 3 types of caprine milk Cheddar cheese: a control cheese (unfortified) and 2 iron-fortified cheeses, one of which used regular ferrous sulfate (RFS) and the other used large microencapsulated ferrous sulfate (LMFS). We then compared the iron recovery rates and the microstructural, textural, and sensory properties of the 3 cheeses under different storage conditions (temperature and duration). Compositional analysis included fat, protein, ash, and moisture contents. The RFS (FeSO₄·7H₂O) and LMFS (with 700- to 800-μm large particle ferrous sulfate encapsulated in nonhydrogenated vegetable fat) were added to cheese curds after whey draining and were thoroughly mixed before hooping and pressing the cheese. Three batches of each type of goat cheese were stored at 2 temperatures (4°C and ?18°C) for 0, 2, and 4 mo. We analyzed the microstructure of cheese using scanning electron microscopy and image analysis software. A sensory panel (n = 8) evaluated flavors and overall acceptability of cheeses using a 10-point intensity score. Results showed that the control, RFS, and LMFS cheeses contained 0.0162, 0.822, and 0.932 mg of Fe/g of cheese, respectively, with substantially higher iron levels in both fortified cheeses. The iron recovery rates of RFS and LMFS were 71.9 and 73.5%, respectively. Protein, fat, and ash contents (%) of RFS and LMFS cheeses were higher than those of the control. Scanning electron microscopy analyses revealed that LMFS cheese contained smaller and more elongated sharp-edged iron particles, whereas RFS cheese had larger-perimeter rectangular iron crystals. Iron-fortified cheeses generally had higher hardness and gumminess scores than the control cheese. The higher hardness in iron-fortified cheeses compared with the control may be attributed to proteolysis of the protein matrix and its binding with iron crystals during storage. Control cheese had higher sensory scores than the 2 iron-fortified cheeses, and LMFS cheese had the lowest scores for all tested sensory properties.     

Texture,physicochemical and sensory properties of artisanal Adobera cheese from Los Altos de Jalisco,a genuine Mexican cheese

Physicochemical and sensory properties of Adobera, a genuine, understudied Mexican raw‐milk cheese, were explored by analysing commercial samples from different manufacturers and seasons. Composition‐wise, Adobera could be considered a fresh cheese with a high moisture content (42.5%), although its relatively low water activity (0.953) and pH (5.14) and high free amino acid content (0.46 mmol/g, dry basis) could indicate otherwise. Instrumental texture corresponded to that of a semifirm cheese, while its colour was whitish‐to‐ivory. Both texture and composition were significantly affected by sampling season and cheese composition, while some attributes of sensory acceptability significantly varied with brand.     

添加酿酒酵母的类Cheddar干酪生产工艺

开发具有特色风味的干酪产品是提高我国消费者对干酪接受度的重要手段。以新鲜牛乳为原料,选取蔗糖添加量、干酪发酵剂添加量、凝乳酶添加量为因素,以干酪产率、感官评定为主要检测指标,通过单因素实验和正交实验对添加酿酒酵母的类Cheddar干酪的加工工艺进行优化,并以感官评定为主要检测指标,对最佳工艺进行验证。结果表明,添加酿酒酵母的类Cheddar干酪的最佳工艺条件为:蔗糖质量浓度50 g/L,干酪发酵剂质量浓度0.02 g/L,凝乳酶活力223.5 IMCU/L。在此优化条件下,成品新鲜干酪的感官评分为76.29,色泽明亮,组织状态结实,奶香味与酒香味浓郁且适宜。     

Nutritional,antioxidant, and antimicrobial assessment of carrot powder and its application as a functional ingredient in probiotic soft cheese

Carrots (the main source of carotenoids) have multiple nutritional and health benefits. The objectives of this study were to evaluate the compositional, antioxidant, and antimicrobial properties of carrot powder and to examine its effect on the sensory characteristics, chemical properties, and microbial viability of probiotic soft cheese at a rate of 0.2, 0.4, and 0.6%. The carrot was turned into powder before being analyzed and incorporated as an ingredient in making probiotic soft cheese. Probiotic soft cheese was made from buffalo milk. The buffalo milk (～6.9% fat, 4.4% protein, 9.2% milk solids not fat, and 0.7% ash) was pasteurized at 75 ± 1°C for 5 min and cooled to 40–42°C. The milk was then divided into 4 aliquots. Sodium chloride (local market, Assiut, Egypt) was added at a ratio of 5% followed by starter cultures. The carrot powder (4.5% moisture, 4.8% ash, 2.7% fat, 8.2% protein, 11.9% fibers, and 72.3% carbohydrate) was added at a rate of 0.2, 0.4, and 0.6%, followed by addition of 0.02 g/kg rennet. The cheese was cut again into cubes, pickled in jars filled with whey, and stored for 28 d at 6 ± 1°C. The results of this study illustrated the nutritional and antioxidant properties of carrot powder. Incorporation of carrot powder in probiotic soft cheese affected the moisture and salt content at 0 d. The total bacteria count decreased from 7.5 to 7.3 log cfu/g in the cheese when carrot powder was used at a rate of 0.6%. The reduction of total bacteria count was noticed during the 28 d of storage by adding carrot powder. Furthermore, lactic acid bacteria and Bifidobacterium longum counts elevated with adding carrot powder during the 28 d of storage.     

Microbial and sensory changes throughout the ripening of Prato cheese made from milk with different levels of somatic cells

The objective of this research was to evaluate the effects of 2 levels of raw milk somatic cell count (SCC) on the composition of Prato cheese and on the microbiological and sensory changes of Prato cheese throughout ripening. Two groups of dairy cows were selected to obtain low-SCC (<200,000 cells/mL) and high-SCC (>700,000 cells/mL) milks, which were used to manufacture 2 vats of cheese. The pasteurized milk was evaluated according to the pH, total solids, fat, total protein, lactose, standard plate count, coliforms at 45°C, and Salmonella spp. The cheese composition was evaluated 2 d after manufacture. Lactic acid bacteria, psychrotrophic bacteria, and yeast and mold counts were carried out after 3, 9, 16, 32, and 51 d of storage. Salmonella spp., Listeria monocytogenes, and coagulase-positive Staphylococcus counts were carried out after 3, 32, and 51 d of storage. A 2 × 5 factorial design with 4 replications was performed. Sensory evaluation of the cheeses from low- and high-SCC milks was carried out for overall acceptance by using a 9-point hedonic scale after 8, 22, 35, 50, and 63 d of storage. The somatic cell levels used did not affect the total protein and salt:moisture contents of the cheeses. The pH and moisture content were higher and the clotting time was longer for cheeses from high-SCC milk. Both cheeses presented the absence of Salmonella spp. and L. monocytogenes, and the coagulase-positive Staphylococcus count was below 1 × 10² cfu/g throughout the storage time. The lactic acid bacteria count decreased significantly during the storage time for the cheeses from both low- and high-SCC milks, but at a faster rate for the cheese from high-SCC milk. Cheeses from high-SCC milk presented lower psychrotrophic bacteria counts and higher yeast and mold counts than cheeses from low-SCC milk. Cheeses from low-SCC milk showed better overall acceptance by the consumers. The lower overall acceptance of the cheeses from high-SCC milk may be associated with texture and flavor defects, probably caused by the higher proteolysis of these cheeses.     

Influence of carboxymethylcellulose on the physicochemical,rheological and sensory attributes of a low‐fat Domiati cheese

The physicochemical, rheological and sensory attributes of a low‐fat Domiati cheese produced using carboxymethylcellulose (CMC), a hydrocolloid, at 0.4, 0.6, 0.8 and 1% (w?w) were examined during the ripening period. Results indicated that, as the carboxymethylcellulose content of cheese milk increased, cheese yield and moisture of low‐fat Domiati cheese significantly increased but the protein, salt and fat values significantly decreased. Rheological parameters were significantly lower in cheeses made with CMC. With regard to the sensory properties of the cheeses, low‐fat Domiati cheese made with 1% (w?w) CMC recorded the highest scores for sensory attributes.     

A comparison of the physicochemical characteristics of the regional cheese Oscypek and the traditional cheese Gazdowski from the Polish Podhale

The quality of two types of traditional cheese manufactured in Podhale (southernmost region of Poland), that is, Oscypek (regional PDO) and Gazdowski (native traditional product ‐ NTP), was compared. The appearance, sensory qualities, proximate composition and intrinsic traits were evaluated. Oscypek manufactured from mixed (sheep and cow) milk received higher sensory scores for texture, taste and aroma than the traditional Gazdowski cheese made from cow's milk. Furthermore, the Oscypek cheese contained significantly more total solids and protein, but less salt. Composition could be responsible for its more cohesive texture which was defined by significantly greater cohesiveness, greater hardness, springiness, shear force and shear energy.     

Effect of the inoculation level of Lactobacillus acidophilus in probiotic cheese on the physicochemical features and sensory performance compared with commercial cheeses

The complex metabolism of probiotic bacteria requires several technological options to guarantee the functionally of probiotic dairy foods during the shelf life. This research aimed to evaluate the effect of the supplementation of increasing amounts of Lactobacillus acidophilus (0, 0.4, or 0.8 g/L of milk) on the physicochemical parameters and sensory acceptance of Minas fresh cheese. In addition, the sensory acceptance of probiotic cheeses was assessed using a consumer test and compared with commercial cheeses (conventional and probiotic). High counts (9.11 to 9.42 log cfu/g) of L. acidophilus were observed throughout the shelf life, which contributed to the maintenance of its probiotic status and resulted in lower pH values and greater production of organic acids. The probiotic cheeses presented lower scores for appearance, aroma, and texture compared with conventional cheeses. Internal preference mapping explained almost 60% of the total variation of the data and showed a large number of consumers concentrated near the conventional cheeses, demonstrating greater preference for these samples. The findings indicated that some negative sensory effects could occur when high level of supplementation with L. acidophilus is used in probiotic cheese processing.     

Influence of storage temperature on the quality of salted mackerel (Rastrelliger kangurta) and pink perch (Nemipterus japonicus)

Dry-salted mackerel and pink perch were stored at two temperatures: ambient (26·8 ± 3·3°C) and 2·5 ± 1°C. Changes in moisture content, salt content, water activity (a_w), peroxide value (PV), free fatty acid content (FFA), total volatile base nitrogen (TVBN) content, halophilic bacterial count and sensory scores for overall acceptability were studied. Loss of moisture and absorption of salt were considerably higher in the products stored at ambient temperature. The decrease in a_w was more pronounced at ambient temperature than at the lower temperature. Although the chemical indices of freshness (PV, FFA and TVBN) and the halophilic counts showed increasing trends, they were considerably lower in the products stored at the lower temperature. Sensory evaluation for overall acceptability indicated that storage at the lower temperature could considerably extend the shelf-life of salted fish.     

Effects of protein and fat levels in milk on cheese and whey compositions

Bulk tank milk was standardised to six levels of fat (3·0, 3·2, 3·4, 3·6, 3·8, 4·0%) and similarly to six levels of protein, thus giving a total of 36 combinations in composition. Milk was analyzed for total solids, fat, protein, casein, lactose and somatic cell count and was used to make laboratory-scale cheese. Cheese samples from each batch were assayed for total solids, fat, protein and salt. Losses of milk components in the whey were also determined. Least squares analysis of data indicated that higher protein level in milk was associated with higher protein and lower fat contents in cheese. This was accompanied by lower total solids (higher moisture) in cheese. Inversely, higher fat level in milk gave higher fat and lower protein and moisture contents in cheese. Higher fat level in milk resulted in lower retention of fat in cheese and more fat losses in the whey. Higher protein level in milk gave higher fat retention in cheese and less fat losses in the whey. Regression analysis showed that cheese fat increased by 4·22%, while cheese protein decreased by 2·61% for every percentage increase in milk fat. Cheese protein increased by 2·35%, while cheese fat decreased by 6·14% per percentage increase in milk protein. Milk with protein to fat ratio close to 0·9 would produce a minimum of 50% fat in the dry matter of cheese.