Dry aging application in home-type refrigerators

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Food Engineering, Turkey

Approval Date: 2015


Supervisor: SERPİL ŞAHİN


Since the popularity of meat aging applications is increasing from day to day in commercial cases or in restaurants, consumers are more aware of the quality enhancement obtained by aging and are more willing to apply aging at home by using their existing refrigerator. For this reason, it was aimed to examine the possibility of dry aging in home-type refrigerators. The combined effects of dry aging conditions (air flow rate and aging period) in a specially designed compartment of home-type refrigerators on meat quality were studied. Paired boneless rib steaks fulfilling US Choice degree standards (n = 48) were obtained from calf carcasses having maturity of A class. Rib steaks taken from carcasses were randomly assigned to one of twelve aging treatments (0.50 m/s ; 0.75 m/s ; 1.00 m/s fan speed and 7, 14, 21 or 28 days of aging period) and kept at temperatures of 0 ± 0.5 °C and humidity averaged 80 ± 4 % during the total aging period. As a novel analysis method, image processing was used for shrinkage analysis and NMR relaxometry was applied to examine internal changes. Besides, microbial analysis (total aerobic bacteria, yeast and mold populations), pH change, water holding capacity (WHC), Warner-Bratzler Shear Force (WBSF), moisture content, trim and cook loss, weight loss, color change, peroxide, p-Anisidine and vi TBARs values were examined to determine physical and chemical changes during aging period. According to the findings; for chemical analysis, time effect was dominant when compared to fan speed effect. Besides, after 21 days a sharp rise was observed in terms of TBARS and p.A.V meaning that rate of oxidation increased after 21 days. NMR T1 and T2 relaxation times were also affected from aging at different conditions and correlated with WHC and moisture content. For physical analysis, both fan speed and aging time were effective on physical quality and with increasing time and fan speed, yield decreased causing economic loss. From another aspect, water holding capacity had the top value on 21 days of aging. In addition, Aerobic plate count pressed in upon limit value in case of 28 days of aging.