Shelf-life quality of Korean traditional "Satae-jjim" prepared by sous-vide and cook chill system

Abstract

The contemporary society, as it becomes more industrialized along with economic development, is undergoing a transformation in its dietary habits with growing dependence on convenience and frozen foods. In the midst of this change, beef consumption hes been rapidly increasing, and consumers have been finding a trend in preference toward cooking methods that capture both high flavor and nutrition at the same time.

“Satae”, a specific beef cut that is not as favorable as other cuts, is used for sous-vide and cook-chill (SV/CC) method to observe the effects of temperature abuse on physicochemical and microorganism properties of the cooked food to determine its resulting storability. “Satae”, the main experimental ingredient, is of the portion that attaches to the bovine patellar region, which undergoes much activity, possesses a dark hue, and is tough in quality, but the cut is known to exhibit good taste upon slow cooking. In Korea specifically, domestic beef contains more vitamin A, vitamin E, and nucleic acid substances that influence the flavor in comparison to imported beef (Yang et al., 2007).

SV/CC cooking method is currently being used in internationally renowned restaurants and preserves nutrients and ingredient quality better when compared to other methods. Vacuum-sealed packaging provides the advantage of reducing microorganism proliferation and extending food shelf life more so than conventional, traditional methods.

Samples used in the experiments were cooked for 120 minutes at 90°C in polyamide-polypropylene plastic bags and sealed in vacuum. After vacuum-packaging, a chiller was used for rapid cooling to 3°C within 2 hours, and the samples were observed for changes at 5°C or 15°C for 36 days. In evaluating the product quality, physicochemical characteristics (pH, water activity, volatile basic nitrogen [VBN], L*a*b*, salinity, texture profile analysis [TPA]) and microorganism (aerobic bacteria, E. coli, coliform bacteria) analyses were performed.

Product quality was evaluated throughout 36 days in 3-day increments for a total of 13 time points and water activity was measured every 5 days for a total of 8 time points. When analyzing the physicochemical properties based on storage duration, significant differences were seen for pH, water activity, L*a*b*, salinity, and TPA but no substantial changes could be observed. In contrast, VBN values rapidly increased from day 27 and exceeded the level of decomposition set by the national Food Code. Microorganism experiments were not significant in either 5°C or 15°C throughout the 36 days.

Storability of the food product was determined based on the VBN results from the physicochemical analysis; the storability is suggested to be 31.7 days at 5°C and 23.8 days at 15°C.