EFFECTS OF SODIUM LACTATE, SODIUM ACETATE AND SODIUM DIACETATE ON MICROBIOLOGICAL QUALITY OF VACUUM-PACKED BEEF DURING REFRIGERATED STORAGE

Beef samples were cut into the pieces and treated with solutions of 1.8 and 2.5% sodium lactate (SL), 0.1% sodium acetate (SA), 0.1 and 0.2% sodium diacetate (SDA) and their combinations, packed under vacuum and stored in a refrigerator at 4C. Microbiological quality of the samples was investigated during their storage for 21 days. Sodium salts and their combinations significantly (P < 0.05) affected the aerobic plate count (APC). Although growth of lactic acid bacteria (LAB), psychrotrophs and coliforms was delayed in treated samples, they were not completely inhibited. The most effective treatment to delay the growth of microorganisms was the combination of 2.5% SL + 0.2% SDA. The count of bacteria of the samples reached and exceeded the spoilage limit (10⁷?10⁸log cfu/g) after 14 days at 4C.     

MICROBIOLOGICAL, SENSORY AND COLOR CHANGES OF ANCHOVY (ENGRAULIS ENCRASICHOLUS) PATTIES DURING REFRIGERATED STORAGE

In this study, the microbiological, sensory and color changes of anchovy patties during refrigerated storage were investigated. Total viable bacteria and psychrotrophic bacteria counts increased, and sensory scores decreased during the storage period. Total bacteria count exceeded the critical limit of 10⁶   cfu/g on day 5. Yeast–molds, Staphylococcus aureus and Escherichia coli were not detected during the storage period. L*, a* and b* values of anchovy patties were changed from 36.8  ±  1.2, 4.67  ±  1.00, 13.0  ±  2.12 to 35.3  ±  3.8, 4.20  ±  0.89, 14.12  ±  2.76, respectively, on day 5. Up to day 4, anchovy patties were determined as "acceptable," but on day 5, they were no longer acceptable according to the results of microbiological and sensory analysis.

PRACTICAL APPLICATIONS

Anchovy is very suitable for patties because of their flavor and taste. In recent years, the increasing numbers of working women of the population have led to direct consumer's preference to ready-to-eat fish foods. For this purpose, anchovy patties were made, and microbiological, sensory and color changes of anchovy patties during refrigerated storage were investigated. The other discarded fish species can be used for making fish patties. The variety of fish patties can be increased and discarded fish can be evaluated on this way.     

EXTRACTION OF ACID-SOLUBLE COLLAGEN FROM GRASS CARP (CTENOPHARYNGODON IDELLA) SKIN

Grass carp is a freshwater fish species widely known by consumers over the world. Its skin has abundant collagen which has many healthy effects. Four variables (acetic acid concentration, temperature, time, solvent to material ratio) were taken to investigate their effects on the extraction efficiency of collagen from grass carp skin. From the results obtained, each of them showed a significant role in the extraction. The yield of collagen increased with the increase of acetic acid concentration to 0.5 M, and thereafter decreased. Elevation of temperature during extraction could also lead to the increase of collagen yield. However, when the temperature was above 20C, a negative effect was observed. The yield of collagen increased with the extension of time, especially when the time was shorter than 24 h. A positive relation was also observed between solvent to material ratio and yield of collagen.

PRACTICAL APPLICATIONS

Grass carp is widely consumed over the world for its delicious taste and healthy effect. A large amount of collagen exists in the skin tissues. Development of collagen from grass carp skin can bring added value for the fish processing industry. In this work, extraction of collagen from grass carp skin was investigated and effects of acetic acid concentration, temperature, time and solvent to material ratio on the extraction efficiency were determined. The results indicated that the above variables were influential for the extraction process. It is important to define the level of these variables in practical application so that the extraction efficiency can be improved, and a time-saving, cost-efficient process can be obtained.     

APPLICATION OF CHITOSAN TO MAINTAIN THE QUALITY OF KAMABOKO GELS MADE FROM GRASS CARP (CTENOPHARYNGODON IDELLUS) DURING STORAGE

Chitosan was added to kamaboko gels made from grass carp ( Ctenopharyngodon idellus ), and the effects on preservation quality were determined by biochemical (pH, total volatile basic nitrogen [TVBN], thiobarbituric acid [TBA], peroxide value) and microbiological (total bacterial count) determinations during storage at 4C. Application of chitosan, at a level of 1% (w/w), exhibited a beneficial effect on inhibiting lipid oxidation and bacterial growth in the gels. The preservative function was related to the molecular weight of chitosans. Relative low molecular weight chitosan showed a higher antioxidant capacity than high molecular weight chitosan. However, mixture of 300 and 10 kDa chitosans exhibited the highest antibacterial activity. Increases of pH, TVBN, TBA and peroxide values in gels during storage were significantly reduced when chitosan was applied. The present study provides a possible application of chitosan as a food additive for surimi-based foods.

PRACTICAL APPLICATIONS

Surimi-based product processing is an effective way to utilize freshwater fish with low commercial value, but the shelf life of surimi products is quite limited. Therefore, preservatives are commonly added to surimi products to extend the shelf life. This research has investigated the effect of chitosan, a natural preservative and antioxidant, on maintaining the quality of grass carp gels during storage at 4C. Results showed that chitosan could inhibit the growth of microorganism and prevent lipid oxidation, which was related to the molecular weight of chitosans. The present study should provide a possible application of chitosan as a natural food additive for surimi foods.     

QUALITY CHANGES OF SARDINE (SARDINA PILCHARDUS) PATTIES DURING REFRIGERATED STORAGE

In this study, quality changes in sardine patties stored at 4C were investigated. Total viable bacteria, psychrotrophic and coliform bacteria counts of sardine patties increased from 2.50 log cfu/g, 2.60 log cfu/g, 19 MPN/g to 6.15 log cfu/g, 6.45 log cfu/g, 70 MPN/g on day 6, respectively. Yeast–molds, Staphylococcus aureus and Escherichia coli were not detected during the storage period. Total volatile basic nitrogen, thiobarbituric acid and trimethylamine nitrogen values of sardine patties were 13.66 mg/100 g, 1.50 mg MA/kg and 1.20 mg/100 g at the beginning and 29.55 mg/100 g, 3.60 mg MA/kg and 5.01 mg/100 g at the end of the storage period (at day 6), respectively. Based on sensory evaluation, the shelf life of sardine patties was determined to be 4 days during refrigerated storage. When chemical, microbiological and sensory analyses were compared, sensory analysis was the found to be most effective for determining the shelf life of sardine patties .

PRACTICAL APPLICATIONS

There is a possibility of consuming sardines as fish patties when catches are large. Sardines are very suitable for patties because of their flavor and taste, and their consumption is very large as fresh fish in Turkey. In recent years, the increase in civilization or socioeconomic factors such as the increasing numbers of working women have led to direct consumers' preference for ready-to-eat foods. Thus, sardine patties were made and quality changes in sardine patties during refrigerated storage were investigated.     

GREEN UMBU (SPONDIAS TUBEROSA ARR. CAM.) PRESERVE: PHYSICAL, CHEMICAL AND MICROBIOLOGICAL CHANGES DURING STORAGE

A preserve made from “umbu” in the green state of maturity represents an alternative to avoid losses of the fruit in the mature stage. A factorial experimental design was used to evaluate the effects of formulation, packaging and storage time (0, 45 and 90 days) on the physicochemical, chemical, physical and microbiological characteristics of the preserve during storage under ambient conditions (33C/88% relative humidity). The results showed that the products were microbiologically stable, but that degradation of soluble pectin, reducing sugars and total soluble solids occurred, especially in the cellophane packaging, and this resulted in textural and color changes in the products. The results suggested the incorporation of pectin and glucose syrup and the use of a polypropylene packaging as being the most adequate method of producing and conserving preserves made from this pulp.     

EFFECT OF SODIUM ALGINATE COATING WITH PRESERVATIVES ON THE QUALITY OF MEAT PATTIES DURING REFRIGERATED (4 ± 1C) STORAGE

Edible coatings are the substances that are used to preserve and enhance food quality. An attempt was made to improve the quality of buffalo meat patties (BMPs) by method of alginate coating involving dipping BMPs during the end of the broiling process in alginate solution with preservatives for 30 s, followed by dipping in calcium chloride solution for 30 s, followed by draining for 30 s. The coated BMPs were kept at refrigeration (4  ±  1C) temperature in a polyethylene bag. They were analyzed for quality changes at regular intervals. Alginate coating significantly ( P ≤  0.05) decreased the overall shear force values, thiobarbituric acid and tyrosine value, total plate count, psychrophilic count, and yeast and mold count. The enterobacteriaceae count could not be detected. The coating at 2% level significantly ( P ≤  0.05) improved the overall appearance and color, juiciness, flavor, texture and overall palatability of the product. During storage, the overall values for shear force, TBA, pH, tyrosine and count for total plate, psychrophilic, yeast and mold, and staphylococcal, increased linearly. The overall sensory scores of the products decreased linearly with storage time.

PRACTICAL APPLICATIONS

Edible coating of meat products provides better protection against oxidative and microbiological deterioration. It can also significantly enhance the sensory qualities of meat products. The freshness of meat products is comparatively prolonged.     

EFFECT OF DIETARY COMPONENTS AND SURFACE APPLICATION OF OLEORESIN ROSEMARY ON LIPID STABILITY OF RAINBOW TROUT (Oncorhynchus mykiss) MUSCLE DURING REFRIGERATED AND FROZEN STORAGE

The effect of dietary supplementation with α-tocopherol and surface application of oleoresin rosemary on the lipid stability of rainbow trout ( Oncorhynchus mykiss ) muscle during refrigerated storage (4C) and frozen storage (−20C) for 8 days and 6 months, respectively, was investigated. A significant (p < 0.05) reduction in α-tocopherol concentrations in muscle tissue during frozen storage was observed. The 2-thiobarbituric acid-reactive substances (TBARS) values of muscle samples, with or without surface application of oleoresin rosemary, increased during storage for all dietary groups. A significant (P < 0.05) interaction between dietary treatments and the time of storage was observed. Muscle tissue from fish receiving a dietary supplement of 500 mg/kg diet had the lowest TBARS values. The oxidative stability of the lipids was further improved by applying oleoresin rosemary to the surface of the fish fillets.     

ROLE OF CARROT ON SHELF STABILITY OF DAIRY DESSERT (RASOGOLLA) DURING REFRIGERATED STORAGE

ABSTRACT

Carotene‐enriched carrots (Daucus carota L. var. Chantenay) were evaluated for their inhibitory effects on acidity development and lipid oxidation in rasogolla during refrigerated storage. Rasogolla is mashed fresh cheese or cottage cheese boiled in rounded shape in concentrated sugar syrup. Six types of rasogolla samples containing carrot paste at 0, 10, 20, 30, 40 and 50% were prepared and stored in closed container at refrigerated condition for 20 days. Chemical changes were measured for acidity of syrup, pH of syrup, free fatty acid content and absorptivity of rasogolla samples, and sensory evaluation of rasogolla samples at days 0, 5, 10, 15 and 20 of storage. The carrot pastes showed significant protection against lipid oxidation, acidity development and sensory quality maintenance in rasogolla. Higher levels of carrot pastes were more effective to increase shelf stability in rasogolla at different tested storage times. However, after day 10 of storage, carrot concentration showed negative result, i.e., enhancement of rate of lipid oxidation of rasogolla samples and its syrups along with visual color destruction. Also, excess quantity of carrot in rasogolla reduces the overall acceptance by the consumer. According to the overall result of shelf stability, it could be suggested that carrot concentration up to 30% should be used in rasogolla for long duration of storage, i.e., above 10 days.

PRACTICAL APPLICATIONS

Traditional dairy products such as Rasogolla are important, well balanced food, which contribute a number of nutrients in relation to our need for good nutrition and health. Rasogollas' projected demand is 6000 tonnes in 2009 ( Karunanithy et al. 2007 ). Carrot is a good source of carotene specially beta‐carotene and serve as a good source of natural antioxidant. Fortification of carrot in dairy product serves as functional or health food for people of all age group. It also imparts a safe and attractive color to the dairy product. Besides, it is also cost effective for the dairy industry, because carrot is much cheaper than milk or channa (a dairy product analogous to cottage cheese). Study on the role of carrot on shelf stability of rasogolla under refrigerated storage is an attempt to establish this new product in the dairy industry.