| Popis: |
To screen the suitable thawing method of frozen beef and better maintain its eating quality and flavor after unfreezing, in this paper, the strip loin frozen at −20 ℃ was taken as the research object, and the naturally frozen one was taken as the control group (CK), the ones with distances of 20, 30, and 40 cm (LVEFT20, LVEFT30, LVEFT40) from the low-voltage electrostatic filed generating plate were taken as the treatment groups, and 2 ℃ was the final temperature of unfreezing. The test method of combining conventional quality with gas chroma-tography-mass spectrometry (GC-IMS) was adopted to compare and analyze the effects of different low-voltage electrostatic field unfreezing on beef quality and flavor. The results revealed that compared with CK, the low-voltage electrostatic field assistance unfreezing treatment could shorten the unfreezing time of beef samples, improve the loss rate of unfreezing juice and cooking loss, cut down on the nutrient loss of unfrozen beef, inhibit the growth of microorganisms, and allow beef to maintain a better color, shear force, and flavor. Among them, the treatment of LVEFT30 was the best. The unfreezing time was 7 hours shorter than that of CK. The unfreezing juice loss rate and protein mass fraction, and cooking loss rate of beef after unfreezing were reduced by 45.79%, 21.32%, and 27.48%, and the shear force was only 66.99 N. Total volatile basic nitrogen (TVB-N), total bacterial count, color, volatile compounds types, and relative contents were similar to those of fresh beef. Therefore, the beef can maintain good quality when frozen beef was defrosted with a distance of 30 cm from the electrostatic plate. This result provides a scientific basis and technical support for unfreezing frozen beef in production. |
