Effects of Vacuum-packaging on the Microbiological, Chemical, Textural and Sensory Changes of the Solar Rack Dried Sardines During Chill Storage

Abstract

Solar dried clupeid sardine fishery storage along the Kenyan coast has always been carried out unhygienically using gunny bags kept under ambient conditions. Shelf life changes of the vacuum-packaged solar rack dried sardines during chill storage were therefore examined, to determine the occurring microbiological, chemical, textural and sensory changes in the gunny bag (GBP), control air (CAP), experimental air (EAP) and Experimental Vacuum Packaged (EVP) samples. Pouches (size: 15×22 cm) made of 12 μ-polyester laminated with 300 gauge low-density polyethylene were used for packaging. After packing, all the packs were iced with flake ice in the ratio of 1:1 and stored maintained in an insulated cooler box at 0-2°C. Thereafter, samples were analyzed periodically for chemical, microbiological, textural and sensory characteristics quality changes. Staphylococcus aureus, Enterobacteriaceae and Feacal streptococci counts were also determined at the packaging time and at sensory rejection time. Ambient stored Gunny bag and polythene air packaged samples had a shelf life of 14 and 30 days, respectively; chilled polythene air-packaged 45 days and chilled vacuum-packaged 90 days. Thus, vacuum-packaging in combination with chilling was found to be the best in delaying spoilage and thereby significantly extending dried fish products shelf life in tropical environments.

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“…However, there was a slight increase in pH (6.2±0.01 -6.3±0.01) in VPSPs during storage of the product. This observation is in agreement with a related study carried out by Ochieng et al (2015) which involved monitoring the effects of vacuum packaging on the chemical properties of solar rack dried sardines during chill storage. The increase in pH reported in this study during storage of VPSP could be as a result of ammonia (volatile base compound) released by spoilage bacterial activities during storage of the product.…”

“…During storage of VPSP at ambient temperature (28±2°C), reduction in pH of the samples (pH 6.2) occurred at Week 4. The slight reduction in pH observed in this study was earlier reported by Ochieng et al (2015) from a related study. However, there was a slight increase in pH (6.2±0.01 -6.3±0.01) in VPSPs during storage of the product.…”

Combined Effect of Moringa (Moringa oleifera) Water Extracts and Vacuum Packaging on the Quality and Lipid Oxidation of the Sun-Dried Punti (Puntius sophore) During Storage

“…However, TVBN values of T1 sample was very near to the rejection limit at 6 month of storage. It has been reported that the lowest TVBN value (5.6 to 19.5 mg/100g) was recorded in vacuum-packaged dried sardine compared to the treated samples during 90 days of storage (Ochieng et al, 2015). Moringa water extract combined with vacuum packaging showed synergistic effect in reducing TVBN value, which reduces the bacterial number or the bacterial deamination property on non-protein nitrogenous compound due to the presence of phenolic compounds in moringa.…”

“…The TVBN indicates the degree of spoilage of fishery product mainly composed of ammonia, primary, secondary and tertiary amines (Ochieng et al, 2015). TVBN value increased from 11.78 to 72.76 mg/100g, 10.78 to 49.29 mg/100g, 10.34 to 44.78 mg/100g, 10.24 to 43.74 mg/100g for the control, T1, T2, and T3 samples, respectively (Fig.…”