EFFECTS OF VACUUM AND MODIFIED ATMOSPHERE PACKAGING ON SHELF LIFE OF ROHU FISH (Labeo rohita) STORED AT REFRIGERATED TEMPERATURE (4°C)

Abstract

The study was conducted to evaluate the effects of vacuum and modified atmosphere packaging on the quality and shelf-life of sliced Rohu fish (Labeo rohita) stored at refrigerated temperature (4°C). The study was conducted at quality control laboratory of the Department of Fisheries in the University of Rajshahi from September 2018 to December 2018. Quality and shelf-life of sliced Rohu fishes were evaluated by biochemical and microbiological analysis by using four types of packaging: (i) without sealed pack (control); (ii) vacuum pack as treatment-1; (iii) MAP-1 (50% CO2 & 50% N2) as treatment-2 and (iv) MAP-2 (50% CO2 & 50% O2) as treatment-3. Samples were analyzed at every 2 days interval during 18 days of refrigerated storage (4°C). Different biochemical parameters such as pH, total volatile base nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS) and total viable count (TVC) of bacteria as a microbiological parameter were evaluated and analyzed throughout the storage period. In all packaging conditions, pH values (were in the range 6.8~7.0) throughout the storage period. No significant (p<0.05) differences were observed on the changes in pH values in all four packaging conditions during the storage period. Changes in TVB-N values were observed significantly lower (p<0.05) at 9th day of storage in samples MAP-1 (2.94±0.59 mg/100g) and MAP-2 (2.66±0.20 mg/100g) pack samples as compared to control (3.90±0.76 mg/100g) samples. In case of PV, MAP1 showed better result compared to MAP2 during the storage period. However, the TBARS value in MAP-2 sample exceeded the acceptable limit (2 mg malonaldehyde/kg) on 9th day of storage. The initial total viable count (TVC) was 4.29 log CFU/g in all packaging conditions during the storage period. When compared with control, significant (p<0.05) lower TVC values were observed on 9th and 12th day of storage in MAP samples. Shelf-life of sliced Rohu fish (Labeo rohita) in refrigerated temperature was in acceptable conditions for 8 days in control samples, 11 days for vacuum pack, 13 days for MAP-2 and 16 days for MAP-1 samples. Among the various packaging techniques, MAP1 showed extended shelf life of Rohu fish stored at refrigerated temperature (4°C).