CHANGES IN BIOGENIC AMINE CONTENTS AND SENSORY QUALITY OF SARDINE (SARDINA PILCHARDUS) STORED AT 4C AND 20C

Biogenic amines (tyramine, putrescine, cadaverine, histamine, spermidine and spermine) in sardine during the storage at two temperatures (4C and 20C) were investigated. Changes in sensory scores were also recorded. Significant differences between storage times were found. The levels of tyramine, putrescine, cadaverine and histamine increased as decomposition of sardine progressed at both 4C and 20C. Spermidine and spermine did not change throughout storage. Putrescine was the main biogenic amine formed, followed by tyramine, cadaverine and histamine. Histamine remained lower than the toxic level of 100 mg/kg in the samples stored at 4C whereas it exceeded the toxic level after 16 h at 20C. The increase in histamine concentration was lower than tyramine and putrescine at both temperatures. Sensory scores gradually decreased during the storage.     

DETERMINATION OF THE QUALITY AND SHELF LIFE OF SOUS VIDE PACKAGED BONITO (SARDA SARDA,BLOCH, 1793) STORED AT 4 AND 12C

ABSTRACT

The aim of this study was to determine the quality and shelf life of sous vide bonito stored at 4 and 12C. The total volatile basic nitrogen (TVB‐N) values of cold stored samples exceeded the recommended limit on 35th day of storage, while they were unacceptable according to sensory scores. The TVB‐N and trimethylamine‐N values of sous vide samples stored at 12C exceeded the limits at the 18th day, while sensory scores were very close to the acceptability limit. For all samples, mesophilic and psychrophilic bacterial counts exceeded the limits after they were regarded as spoiled. Therefore, the shelf life of the sous vide bonito, cooked at 70C for 10 min, was 28 days at 4C while 15 days at 12C. It was seen that sous vide packaging provided a long shelf life for bonito.

PRACTICAL APPLICATIONS

Sous vide is a long established but relatively little known cooking process. The data regarding the effect of storage temperature on shelf life and quality of sous vide fish are very limited. Therefore, this study aimed to determine the sensory, microbiological and chemical quality of sous vides packaged bonito during refrigerated storage (4 ± 1C) and abuse temperature conditions (12 ± 1C). The results of this study can be utilized by researchers in future studies as well as by manufacturers to determine the processing and storage conditions of sous vide fish.     

QUALITY CHANGES IN JICAMA ROOTS STORED AT CHILLING AND NONCHILLING TEMPERATURES

Mature jicama roots (Pachyrhizus erosus (L.) Urban cv. Agua Dulce) were stored at 5, 10, 13 and 20C for 1, 2 or 3 weeks and then transferred to ambient conditions (18–23C) for 1 week. Storage of roots at 5C and 10C for 2 weeks resulted in chill-induced decay and loss of intact root firmness. Increased rates of water loss after storage was another indicator of chilling injury; poststorage water loss rates after storage at 5C and 10C were double the rates of roots stored at 13C and 20C. With storage for 2 weeks, the pulp of roots stored at 10C showed brown discolored areas and this was best represented by decreasing L* values. The grey, translucent aspect of the pulp of roots stored at 5C resulted in L* values intermediate between those at 10C and 13C. Force to penetrate the pulp with a 5 mm probe decreased at 10C, but increased at 5C. The distance to rupture point increased at 5C and 10C, indicating loss of crispness. Jicama roots stored at 13C and 20C maintained good external visual quality and a white crisp pulp.     

EFFECT OF SPICES ON GROWTH AND SURVIVAL OF SALMONELLA TYPHIMURIUM DT 104 IN GROUND BEEF STORED AT 4 AND 8C

Few studies have addressed the use of spices against pathogens associated with meat. The effects of garlic, ginger and turmeric were evaluated against Salmonella Typhimurium DT 104 that were inoculated either in spice paste or in buffered peptone water (BPW) or in heat‐treated ground beef and stored at 4 and 8C for 10 days. Data from the spice pastes study showed a decrease in Salmonella Typhimurium DT 104 counts, and the greatest reduction (3.39 log) was observed in garlic paste stored at 4C. Garlic in BPW data showed a reduction of 1.5 and 1.0 log in Salmonella Typhimurium counts at 4 and 8C, respectively. Ground beef stored at 4C showed no growth or a slight reduction in growth in samples with spice, while all samples at 8C showed an increase in Salmonella Typhimurium counts. Results show that the spices inhibit or inactivate Salmonella Typhimurium DT 104 when they are in direct contact. However, when spices are added to a complex food system such as ground beef, the inhibitory activity of these spices considerably decreases.     

STABILITY OF FROZEN TROUT II. DIFFERENT TROUT PREPARATIONS STORED AT -18°C

Rainbow trout fillets, dorsal fillets, and minces made from the ventral and caudal portions cut away from the dorsal fillets and from the waste portions after filleting, vacuum packed and either untreated or treated with additives (3% sorbitol + 0.5% MSG + 0.02% BHA + BHT (fat content)), were found to be suitable for consumption after one year's storage at ?18°C. Since all the lots were well-preserved under these storage conditions, they may be appropriate for marketing trout products.     

PHYSICOCHEMICAL PROPERTIES OF MUSCLE AND NATURAL ACTOMYOSIN EXTRACTED FROM FARMED ATLANTIC SALMON (SALMO SALAR) STORED AT 4C

Properties of farmed Atlantic salmon (Salmo salar) obtained commercially were studied as a function of storage at 4C for 9 days. While pH increased gradually during storage for both samples, significant differences between samples were noted in water‐binding capacity (WBC) of muscle, as well as surface hydrophobicity (S_o) and sulfhydryl contents of extracted natural actomyosin (NAM). Lower S_owas observed for NAM extracted from muscle stored for 2 days, coinciding with high WBC of the muscle. In contrast, higher S_ofrom 5 to 7 day‐stored samples coincided with minimum extractability and high apparent viscosity of NAM. Reactive sulfhydryl groups were higher at the beginning and end of storage. Generally, WBC of fish muscle was dependent on pH and related to changes in S_oof NAM, while apparent viscosity increased with S_oand disulfide content. The results indicate variability in functional properties of the salmon samples during cold storage, which could be attributed to changes in physicochemical properties of NAM.     

TEXTURAL AND SENSORY PROPERTIES OF α-AMYLASE TREATED POI STORED AT 4C

Poi, a purplish paste made of cooked taro (Colocasia esculenta), hardens rapidly to a rubbery gel at a refrigeration temperature of 4C. This gelling phenomenon was averted by an addition of α-amylase in poi prior to refrigeration. Two sources (porcine pancreas and Aspergillus oryzae) of the enzyme were compared at usage levels of 200 units and 2,000 units. Both the viscosity readings and textural analyses indicated that the enzymatic treated poi maintained a fresh-poi like softness. The α-amylase from porcine pancreas exhibited the least effect at the 200 unit level, while the α-amylase from Aspergillus oryzae caused a slight thinning of the starch staple. The sensory evaluation indicated that the textural attributes were in agreement with the instrumental measurements. Their flavor profiling indicated a loss of the taro taste, however, no off-flavor was observed from the enzymatic treatment at 4C for up to seven days.     

LIPID CHANGES IN FROZEN STORED FILLETS FROM PRE- AND POSTSPAWNED HAKE (MERLUCCIUS HUBBSI MARINI)

The lipid composition of frozen stored fillets from pre‐ and postspawned hake was studied. The total lipid (TL) content in the chloroform/methanol extract from unfrozen postspawned hake was four times higher than that of prespawned fish. After freezing, the TL content of postspawning hake muscle remained unchanged whereas the TL extracted from prespawning fish muscle increased about 90%. The TL extractability of muscle from fish in both different gonadal conditions was not affected by frozen storage. Lipolysis in frozen stored fillets from prespawned hake occurs principally by hydrolytic action on phospholipids (PL), and phosphatidylcholine was the main PL hydrolyzed. Triacylglycerols were the main substrates hydrolyzed in frozen stored fillets from postspawned hake. Freezing and frozen storage affected polyenoics and n‐3 fatty acids (FA). The decrease in the contents of n‐3 FA in fillets from postspawned hake was lower than that observed in fillets from prespawned fish.     

QUALITY CURVES FOR MANGO FRUIT (CV. TOMMY ATKINS AND PALMER) STORED AT CHILLING AND NONCHILLING TEMPERATURES

“Tommy Atkins” and “Palmer” mangoes were harvested medium‐ripe held for 7–20 days at five different temperatures and evaluated for quality attributes. The objective of this work was to obtain quality curves at chilling and nonchilling temperatures and to identify, for each temperature, which quality factors limit mango marketability. Chilling injury and increased fruit softness were the limiting quality factors for mango stored at 2 and 5C. Softening of the fruit, changes in color and development of decay were the limiting quality factors for mango stored at 12, 15 and 20C. Prediction of mango shelf life calculated from the data reported in the literature is not precise unless the characteristics of the fruit and environmental factors involved are well known. The curves obtained from quality evaluations for each temperature showed that a single quality attribute cannot be used to express loss of quality of mango over the normal physiological range of temperatures.     

POSTMORTEM BIOCHEMICAL AND TEXTURAL CHANGES IN THE ADDUCTOR MUSCLE OF CATARINA SCALLOP STORED AT 0C

Postmortem characteristics of the adductor muscle of the Catarina scallop were evaluated for biochemical, chemical and textural changes during a 15‐day storage period in ice (0C). K‐value, pH, nitrogen of trimethylamine (TMA‐N), nitrogen of total volatile bases (TVB‐N), water‐holding capacity (WHC), color and texture changes were monitored. K value increased linearly from an initial value of 20.5 to 68.5% at day 15. Spoilage indicators TVB‐N and TMA‐N (mg/100 g) increased from 13.5 and 2.6 to 21.4 and 3.4, respectively. However, they remained below critical limits, suggesting low microbial activity. In contrast, texture, pH, WHC, and color were not affected. Overall results indicated that the quality of iced Catarina scallop adductor muscle packed in ice was maintained over a period of 15 days.     

DEGRADATION OF ACTIN BY CATHEPSINS IN BEEF FIBERS STORED AT 20C

The degradation of actin throughout 48 h of postmortem storage of muscle fibers at 4 and 20C was studied by means of SDS-gel electrophoresis and immunoblotting using a commercial monoclonal antibody. Electrophoretic patterns showed an enhanced proteolysis of meat held at 20C, as revealed by the increased number and intensity of degradation peptides in the region of 30 kDa, as well as by the appearance of a new peptide of a molecular weight between those of actin and troponin T. Western blotting of actin demonstrated its degradation at 20C, while not at 4C; at least a peptide originating from actin was evident at the former temperature. When fibers were incubated at 20C in the presence of cathepsin inhibitors E-64 and pepstatin, which do not inhibit calpains, the immunoblots showed no degradation of actin. This clearly demonstrated that cathepsins are effectively involved in actin degradation in fibers stored at 20C.     

BIOCHEMICAL PROPERTIES OF ACTOMYOSIN AND EXPRESSIBLE MOISTURE OF FROZEN STORED ADDUCTOR MUSCLES OF PATAGONIAN SCALLOP (ZYGOCHLAMYS PATAGONICA)

The biochemical properties of actomyosin and the expressible moisture of frozen stored adductor muscles of scallop (Zygochlamys patagonica) were investigated. After freezing (zero time of storage) both the enzymatic activity and the reduced viscosity of actomyosin remained unchanged with respect to those corresponding to actomyosin from unfrozen muscles. Both parameters significantly decreased (P < 0.01) at 4 months of frozen storage and thereafter gradually decreased. No significant differences (P > 0.01) were observed in the relative percentages of myosin, actin, and in the myosin/actin ratio up to 4 months of storage. Thereafter myosin significantly decreased (P < 0.01) up to the end of storage. The decrease in the biochemical properties of actomyosin was accompanied by a loss in the water holding capacity of the muscles.     

STABILITY OF FROZEN TROUT I. TREATED AND UNTREATED MINCES STORED AT -12, -18, and -24 °C

Minced trout, either untreated or treated with additives (3% sorbitol + 0.5% MSG + 0.02% BHA + BHT (fat content)), was found to be acceptable over one year's storage at either ?12, ?18, or ?24°C. The treated samples maintained optimum quality levels over the entire period at each of the storage temperatures tested. Quality was assessed by both objective and subjective methods.     

SHELF LIFE AND BIOCHEMICAL COMPOSITION OF BONITO FISH (Sarda sarda, BLOCH, 1758) STORED AT 4C AND FISHING WITH DIFFERENT FISHING TOOLS

This study was carried out to determine the effects of harvesting method and refrigerated storage on biochemical composition of Atlantic Bonito. Samples were fish caught with a surround trammel net and a drift net in the Middle Black Sea region by fisherman and were brought to the laboratory. Quality control analyses for soluble solid, protein, fat and ashes were performed. On the 10th day after refrigerated storage (4C), pH, total volatile base nitrogen (TVB-N), trimethylamine (TMA-N) and thiobarbituric acid (TBA) values were found in the drift net. In the fresh fish samples caught by surround trammel net and drift net, fat, proteins, soluble solids and ash contents were calculated.

PRACTICAL APPLICATIONS

The results of the proximate content of Atlantic bonito caught with a trammel net and drift net showed that fat contents were 5.76; protein contents were 20.35; dry matter contents were about 30.5% and ash contents was 1–1.2%. After 10 days of storage at 4C, pH, TVB-N, TMA-N and TBA values were 6.17, 34.46 mg/100 g, 7.34 mg/100 g and 7.72 mg malonaldehyde/kg, respectively, in the surround trammel net, and 5.98, 40.60 mg/100 g, 8.02 mg/100 g and 8.03 mg malonaldehyde/kg in the drift net, respectively. Based on these results, there were significant differences between surround trammel net fishing and drift net fishing in terms of meat quality.