DEVELOPING QUICK THAWING PROTOTYPE IN HOUSEHOLD REFRIGERATORS BASED ON CURRENT TECHNOLOGY, AND EXPERİMENTAL INVESTIGATION OF THAWING BEHAVIOR OF MEAT AS MODEL FOOD
Project no. 24168 · Status: Kapanmış · 2022
Summary
<p>Freezing and thawing processes play a critical role in food preservation by delaying microbial spoilage and maintaining product quality. This thesis investigates the thawing behavior of lean beef round samples with different sizes, previously frozen at different freezing rates, using three distinct thawing methods. The effects of thawing on the physical, chemical, and microbiological quality parameters of the meat were evaluated. Both conventional (+4 °C refrigeration) and innovative thawing techniques (ultrasonic, microwave, and a specially designed rapid thawing cabinet) were comparatively analyzed. In the experimental setup, meat samples of various sizes (fillet, diced, minced) frozen at −24 °C in a domestic freezer were thawed using the aforementioned methods. Additionally, fillet samples were subjected to slow freezing (−18 °C in a freezer compartment) and rapid freezing (−24 °C using a custom-built quick-freezing cabinet), and the effects of freezing rate on thawing performance and quality parameters were investigated. After each thawing process, the samples were cooked to assess post-thawing physical and chemical quality characteristics.</p><p>The results indicated that thawing in a refrigerator, although microbiologically safe, requires prolonged thawing time. This method best preserved structural integrity in fillet samples. Ultrasonic thawing significantly reduced the thawing time, but it also increased drip loss and oxidation, particularly in minced meat. Microwave thawing offered the fastest thawing performance; however, at higher power levels, it caused uneven heating, surface overheating, and localized cooking, negatively affecting product quality. The most promising results were obtained with the rapid thawing cabinet developed specifically for this study. This system greatly reduced thawing time without causing thermal damage to the meat surface, enabling a homogeneous thawing process. Especially in fillet samples, this method preserved quality characteristics closest to fresh meat. Rapidly frozen samples exhibited less structural and moisture loss during thawing, while slowly frozen samples showed more tissue damage and drip loss due to the formation of larger ice crystals. The findings of this study highlight that selecting an appropriate thawing method should consider the size of the meat, the freezing rate, and the thawing technique. The rapid thawing cabinet stands out as an energy-efficient, safe, and quality-preserving solution, offering significant advantages for both industrial applications and household use.</p><p>This research contributes valuable insights into the comparative performance of traditional and novel thawing techniques in meat processing. The integrated evaluation of post-cooking quality parameters, combined with an industry-relevant quick-thawing system, underscores the practical applicability of the study. By analyzing the interaction between freezing rate and thawing method, the study presents a comprehensive perspective and addresses a notable gap in current food processing literature.</p>