INFLUENCE OF DIFFERENT TEMPERATURES APPLIED DURING REFRIGERATION AND FREEZING ON BROILER MEAT TEXTURE AND TECHNOLOGICAL FEATURES

L. Solomon, P.C. Boişteanu, M.M. Ciobanu, Roxana Lazăr, R.M. Radu-Rusu

Abstract
   This research is a follow-up of previous original investigations on the influence of the temperature used during the cold treatment of broiler meat in the slaughterhouse on its nutritional quality. Hence it was found that total water content, dry matter and energy content was influenced by the temperature variations in scalding, chilling and storage, we tried to investigate whether the textural and technological parameters are also affected by such variation, both in refrigerated and frozen meat. Three groups of carcasses were studied for the refrigeration flow (one control - RC, two experimental - R1 and R2), varying the experimental factor, temperature, during scalding (RC=51-53°C, R1=53-54°C, R2=55-56°C), during chilling (RC=1-4°C, R1=2-3°C; R2=1-2°C), during sorting-packaging (RC below 2°C; R1=8-10°C; R2=6-8°C), throughout storage prior to delivery to market (RC=0-2°C; R1 and R2=0-1°C). Also, for the frozen meat, three groups were set (FC, F1, F2), providing them the same graduations of the experimental factor like in the refrigerated groups, in the pre-freezing stages (scalding, chilling, sorting), while in the fast freezing moment, the temperature varied accordingly (control FC=-30…-35 °C, F1=-32…-33 °C, F2=-33…-34°C). The biological material comprised 90 ROSS-308 broiler carcasses in refrigeration flow (30 per group) and 90 ROSS-308 broiler carcasses in freezing flow. Pectoral muscles were used from each carcass in pieces weighing 250 grams and were shaped in rectangular chops of 5 cm length x 1 cm width x 1 cm depth along the muscle fibers, to be submitted for shear force (SF) reading (N/cm²) using a Waner Bratzler (WB) chamber. Also, the same muscles were used to sample 100 g pieces to be submitted to drip loss (DL) via tube centrifugation and cooking loss (CL) analysis via boiling in sealed plastic bags. The analytical tests were carried on in duplicate per each sample. SF proved to increase as the temperature in scalding and sorting packaging was higher, due probably to more intense water loss and concentration of dry matter, which led to firmer meat: 22.48 N/cm² in CR, 22.96 N/cm² in R1 (P<0.05) and 23.11 N/cm² in R2 (P<0.01). The preservation through freezing acted as a tenderizer, probably due to connective tissue and to myocytes membranes disruptions: 22.48 N/cm² in CF, 22.96 N/cm² in F1 (P<0.01) and 23.11 N/cm² in F2 (P<0.001). However, it should be investigated to what extent the destruction of the connective stroma due to ice crystals really acts toward tenderizing, because losing the structure eventually lead to poor texture and lower juiciness. The technological parameters of the breast meat varied accordingly, following the shear force progression, thus the samples with higher WB values had lower DL and CL, with variations within the -2.5…-7.9% range (P<0.001), comparing to the ones which were more tender, in appearance. Follow up: sensorial analysis using trained panel of tasters, in comparison with the instrumental analysis of the textural profile.