Study On Processing Technology And Quality Change Of Pre-conditioned Cold-fresh Steak

In this experiment,the best formulation of pre-conditioned cold fresh steak and the best ratio of natural preservative were determined by using single-factor experiment and orthogonal experiment.Changes in texture characteristics and sensory evaluations at different slice thicknesses were determined,and the optimal slice thickness of pre-conditioned cold fresh steak was obtained.The changes of edible quality of vacuum-packed pre-conditioned cold steak at 4°C were studied.Combined with electronic nose measurement,a pre-conditioning cold-fresh steak at 4°C was established.Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry(GC-MS)was used to detect volatile flavor compounds in different pre-conditioning cold steaks under different cooking oils and different cooking methods.The main results were as follows.1)Sensory evaluation and TPA determination were performed on pre-conditioned cold fresh steaks with slice thicknesses of 1 cm,1.5 cm,2 cm,2.5 cm,and 3 cm.The hardness of the pre-conditioned cold fresh steak with a slice thickness of 1.5 cm was significantly lower than that of other slice thicknesses.Samples(p<0.05)showed no significant difference in the chewability of the samples with a slice thickness of 1.5 cm and a slice thickness of 2 cm(p>0.05),but were significantly lower than those of other slices(p<0.05).The sensory scores of the samples with a slice thickness of 1.5 cm were significantly higher than those of other slice thicknesses,so the optimal slice thickness of the pre-conditioned cold fresh steaks at 1.5 cm was finally selected.2)With sensory evaluation as an index,the single-factor experiments and orthogonal experiments were performed on the amount of salt added,the amount of chili powder added,the amount of pepper powder added,and the amount of garlic added in the marinade to determine the optimal formula for the pre-conditioned cold steak.For: salt 1.25%,pepper powder 3%,pepper powder 1%,minced garlic 3.5%.3)Single factor experiment and orthogonal experiment were performed on four natural preservatives to determine the optimum proportion of pre-conditioning cold-fresh steak preservatives: Nisin 0.04%,sodium lactate 4.00%,tea polyphenols 0.03%,natamycin 0.02 %.4)The total colony counts and TVB-N valuesof pre-conditioned cold steaks during storage period at 4°C showed a continuous increase trend,reaching the storage end point on the 24 th day of storage,and the pH value decreased during the early storage period and then showed an upward trend.The cooking loss did not change significantly in the early stage of storage,but increased in the later stage.During the storage period,the L* value and a* value of the pre-conditioned cold fresh steak all showed a downward trend,and the b* value showed an upward trend.In the TPA analysis,the hardness,elasticity,and chewiness of pre-conditioned cold steaks all showed a downward trend.5)The electronic nose was used to distinguish samples with different storage times and the discrimination was good.The correlation between the odor intensity response of the electronic nose and the total number of colonies and the TVB-N value was established by partial least squares analysis.A prediction model for the shelf life was established.The correlation coefficients were all over 0.900,and the model establishment was effective.6)Sensory evaluation was performed on pre-conditioned cold fresh beef steaks processed by different cooking methods.The sensory scores of the fried samples were significantly higher than those of the vacuum-low temperature plus fried samples and the advanced decoction and then baked samples(p<0.05).There was no significant difference in sensory scores between samples prepared by low temperature treatment and those prepared before being fried and then baked(p>0.05).TPA assay showed that the hardness and chewiness of the prepared pre-conditioned cold steaks were significantly lower than those of the other two treatments(p<0.05),while the hardness and chewiness of the samples that were first cryopreserved at low temperature were significantly lower than those of the first two samples.Samples were fried and then baked(p<0.05).There was no significant difference in elasticity between the three groups of cooking methods(p>0.05).7)Four different pre-conditioned cold steaks fried in frying,buttered steaks detected 50 volatile flavors,and the relative content was 98.92%.The olive-fried steak detected 50 volatile flavors.The relative content was 95.57%.The rapeseed oil detected 43 kinds of volatile flavor substances,and the relative content was 94.73%.Soybean-fried steaks detected 47 volatile flavors with a relative content of 97.28%.Butter-fried samples detected the most volatile species and the most relative volatile flavors.The volatile flavor substances brought by the pickling preparations in the volatile flavor substances detected accounted for most of the volatile flavor substa nces,and the characteristics and rules of the volatile flavor substances of the fried beef steaks for different preparations could not be obtained.