Effect Of Different Treatment On Storage Of Fresh-cut Apple Slices

To find a safe and fresh-keep method to fresh-cut apples, effects of treatment with heat, citric acid, lysozyme, sodium erythorbate and chitosan on quality and physiology of fresh-cut ‘Hanfu’(Malus domestica Borkh.cv.‘Hanfu’) apple slices were investigated. The best technical parameters of the treatments was screened by physiological, biochemical and microbiological indexs combined with fuzzy sensory evaluations. Finally, parameters for optimal combination of the selected presrevative and vacuum packaging has been determined.The conclusions were described as follows:To determine the effect of heat treatment on quality and storage of fresh-cut “Hanfu” apple, slices of the fresh-cut apple were packed by 0.11 mm thickness of PE film and stored at 4℃after dipping in 50℃, 60℃ and 70℃ hot-water solution for 2min. The results indicate that appropriate heat treatment kept sensory quality of, inhibited nutritional loss of and reduced microbial levels in the cut apple slices. Heat treatment at 50℃ exerted the most preservation effect on fresh-cut apple slices stored at 4℃ for 8d.To investigate the effect of treatment with 0.5%, 1.0% and 1.5% citric acid solutions for 2min on quality and storage of fresh-cut “Hanfu” apple slices, the slices were packed, after treatment, in 0.11 mm thickness of PE film bags and stored at 4℃ for quality and storage evalutation. The results show that treatment with 1.5% citric acid exerted the best preservation effect for 8d during storage at 4℃ with the process of flesh browning effectively delayed and browning degree reduced, and decreasing of hardness, TSS, titratable acids, Vc, relative conductivity, MDA increase, activities of PPO and POD inhibited.To investigate the effect of lysozyme coating on quality and storage of fresh-cut “Hanfu” apple slices, the fresh-cut slices were packed by 0.11 mm thickness of PE film and stored at 4℃after dipping respectively in 0.01%, 0.05% or 0.08% lysozyme solution for 2min. The results indicate that lysozyme coating inhibited the increases of relative conductivity, malondialdehyde content, polyphenol oxidase activity and total bacterial count, while significantly maintained the peroxidase activity. The quality of fresh-cut apples slices treated with lysozyme was effectively good for 8d after storage with the sensory evaluation, hardness, color, soluble solids and ascorbic acid at higher levels as compared with the control. Of all the 3 concentrations of lysozyme coating tested, treatment with 0.08% lysozyme exerted the best preservation effect.To investigate the effect of treatment with 0.5%, 1.0% or 1.5% sodium erythorbate solution for 2min on storage quality of fresh-cut ‘Hanfu’ apple slices, the slices were packed, after treatment, in 0.11 mm thickness of PE film bags and stored at 4℃ for quality and storage evalutation. The results show that treatment with sodium erythorbate could keep sensory quality, inhibit nutritional loss, and reduce microbial levels in the treated apple slices. Treatment with 1.5% sodium erythorbate exerted the best preservation effect for 8d at 4℃ with the process of flesh browning effectively delayed and browning degree reduced. Decrease in hardness, TSS, titratable acids, Vc and relative conductivity, and increase in MDA and activities of PPO and POD in the fresh-cut apple slices treated with 1.5% sodium erythorbate were all inhibited.To determine the effect of chitosan treatment on quality and storage of fresh-cut “Hanfu” apple, slices of the fresh-cut apple were packed by 0.11 mm thickness of PE film and stored at 4℃ after dipping in 0.5%, 1.0% and 1.5% chitosan solution for 3min. The results indicate that appropriate chitosan treatment kept sensory quality of, inhibited nutritional loss of, reduced microbial levels, suppressed of polyphenol oxidase activity and increased the peroxidase activity in the fresh-cut apple slices. chitosan treatment at 1.0% exerted the most preservation effect on fresh-cut apple slices stored at 4℃ for 12 d.To determine the effect of different edible coatings and heat treatment on quality and storage of fresh-cut “Hanfu” apple in vacuum packing, slices of the fresh-cut apple were packed by 0.08 mm thickness CPP film and stored at 4℃ after dipping in 1.5% citric acid solution, 1.5% ascorbic acid sodium solution, 0.08% lysozyme solution or 50℃ hot-water, respectively, for 2min. The results indicate that all the treatments exerted effect to keep sensory quality of, inhibited nutritional loss of and reduced microbial levels in the cut apple slices. Treatment with 1.5% ascorbic acid sodium solution showed the most best preservation effect on fresh-cut apple slices stored at 4℃ for 15 d.All of the results show that, heat treatment at 50℃, 1.5% citric acid, 0.08% lysozyme, 1.5% sodium erythorbate, 1.0% chitosan compared to other test groups exerted better effect to maintain the fresh-cut apple storage quality. Effect of vacuum packaging with CPP film combined with these treaments on quality and starage of fresh-cut apple decreased in turn by the order: 1.5% sodium erythorbate, 0.08% lysozyme, 1.5% citric acid, 50℃ heat and control.