Quality and shelf life of low fat restructured turkey meat loaf

Abstract

The health conscious consumers prefer low fat meat products and therefore, the present study was designed to develop a suitable formulary for low fat restructured turkey meat loaf and to assess its physico-chemical and cooking characteristics, sensory qualities, proximate and mineral composition, nutritional value, shelf life and cost of production. Four different formulations, viz., low fat control loaf without fat or fat replacer (LFC), added fat control loaf with 10 per cent sunflower oil added on meat weight basis (AFC), low fat loaf with 0.2 per cent carrageenan (CG) and low fat loaf with 4 per cent nonfat dry milk (NFDM) using skinless lean white and dark turkey meat (2:1), curing ingredients, spices and condiments were prepared. The baked loaves were sliced, packaged aerobically and under vacuum in high density polyethylene and polyamide-polyethylene pouches, respectively. The shelf life of the loaves at 0-4oC for 40 days and -20oC for 60 days were evaluated based on 2-thiobarbituric acid reactive substances value (TBARS), sensory qualities, moisture, protein and fat contents. The pH of the loaves with fat replacers was more (P< 0.05) than the uncooked loaf mix in the range of 5.8-6 and could be considered low acid food. NFDM had the highest (P< 0.05) percentages of 93.29 cooking yield, 65.82 moisture retention (MRP) and 108.7 fat retention (FRP). Carrageenan improved (P< 0.05) the cooking yield and MRP but not FRP. The fat replacers significantly reduced the shear force of the loaves. The percentage of moisture, protein, fat and ash in the mixture of skinless turkey white and dark meat were 75.08, 20.79, 2.11 and 0.95, respectively. The white meat is an excellent source of protein and minerals with the least amount of fat. As the percentage of fat in CG and NFDM were 1.53 and 1.57, respectively they can be labeled as ‘low fat’ as per regulations (<3). Moisture loss on baking was significantly lower for CG and NFDM. but it did not affect other components. The per cent contribution of protein in CG and NFDM to the RDA were 26.21 and 26.83, respectively. Addition of nonfat dry milk significantly increased the percentage of carbohydrate, ash, K, Ca and P and their contribution to RDA. The percentage RDA of calories from fat was 0.63 and 0.64 for CG and NFDM, respectively and below the recommended 30 per cent. The TBARS values of the low fat loaves were lesser than the acceptable range of 1mg malonaldehyde/kg loaf for oxidative rancidity, irrespective of packaging and period of storage. Carrageenan and nonfat dry milk had no significant influence on reducing lipid oxidation. The fat replacers increased the sliceability, flavour, juiciness and overall acceptability of the low fat loaves on day zero but it did not affect the texture, saltiness and mouth coating. NFDM was rated higher for colour, flavor and overall acceptability than CG. The packaging, addition of fat replacers and period of storage at 0-4oC and -20oC for 40 and 60 days, respectively did not affect the appearance, colour, texture and mouth coating. Even though the flavour, juiciness and overall acceptability of the packaged loaves with fat replacers reduced (P< 0.05) on storage, these were moderately acceptable up to 40 and 60 days at 0-4oC and -20oC, respectively. Carrageenan and vacuum packaging enabled in retaining flavour and juiciness on storage. Irrespective of the period of storage and packaging a significant reduction in the moisture and corresponding increase in protein and fat of all loaves was noticed on d 60 of storage at -20oC. The cost of production per kg of CG and NFDM were Rs.167/= and Rs.164/=, respectively. The recipes for a low fat (<2 per cent) restructured turkey loaf with 0.2 per cent carrageenan and 4 per cent nonfat dry milk were developed economically with good overall acceptability, cooking yield, nutritional value and shelf life up to 40 and 60 days at 0-4oC and -20oC, respectively under aerobic and vacuum packaging systems.