Preliminary study on the effects of the hottest ca

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Preliminary study on the effect of calcium and browning inhibitors on fresh cut pineapple

abstract the purpose of the study is to screen factors that have an important impact on the color and hardness of fresh cut pineapple. Orthogonal design was used in the experiment. Pineapple fan slices were soaked in 0% and 0.5% sodium isoascorbate, citric acid, sodium hexametaphosphate, EDTA and calcium chloride solutions for 3 minutes. After the surface solution was dried, it was packed in polystyrene plastic trays (5 tablets per plate, about 25g per tablet) and wrapped and sealed with PVC film. It was stored at 10 ℃ for 7 days; The l*, a*, b* and hardness of pineapple slices were measured on the first and seventh days after treatment. The results show that in α= At the level of 0.05, only sodium isoascorbate significantly inhibited the changes of l*, a*, b*; All five reagents had no significant effect on the hardness of fresh cut pineapple

key words: fresh cut pineapple; Browning inhibitor; Calcium chloride

fresh cut fruits and vegetables refer to fresh fruit and vegetable products that are 100% edible from fresh fruit and vegetable raw materials after cleaning, peeling, trimming, cutting, packaging, etc., also known as "minimum processed fruits and vegetables". At present, in developed countries and some developing countries (such as Thailand), China's "energy saving and new energy vehicle industry development plan (20112020)" proposes that the sales of fresh cut fruits and vegetables will increase year by year due to the increasing demand of consumers for convenient and fresh food. Pineapple is an important tropical fruit, with rich flavor, sweet and sour taste, which is very popular with consumers; However, due to the difficulty of peeling pineapple, it is inconvenient to eat it, which affects people's desire to buy. Fresh cut pineapple not only maintains the characteristics of fresh pineapple, but also is convenient to eat and has a good market prospect

the quality problems of fresh cut fruit and vegetable products such as microbial reproduction, browning and softening due to processing trauma have become a major problem affecting the development of fresh cut fruit and vegetable processing industry. According to Marlene and rodriguez[1], pineapple raw materials were properly cleaned and disinfected. The processed fresh cut pineapple was stored at 4 ℃ for 17 days. The total number of bacteria, yeast and mold content of the product met the standard, and no pathogenic bacteria such as Escherichia coli and Listeria were detected. O 'Connor Shaw et al. [2] also showed that the main problem of fresh cut pineapple after 6 days of storage at 4 ℃ is browning rather than microbial corruption

the purpose of this study is to stack single-layer materials (such as plastic film or non crimped fabric plus plastic film) in the hot press layer by layer to explore the effects of calcium chloride, a commonly used hardener for fruits and vegetables, and several commonly used browning inhibitors on the hardness and color of fresh cut pineapple, so as to screen important factors for further parameter optimization design (response surface design RSM) experiments

1 materials and methods

1.1 raw materials

fresh pineapple is purchased in Bangkok market, Thailand. It is phuchet variety, and the peel turns slightly yellow; Select fruits free of pests and mechanical injuries and store them at 13~15 ℃ for one night. The reagents used are sodium isoascorbate (SE), citric acid (CA), EDTA, sodium hexametaphosphate (nahmp) and calcium chloride (CaCl2) of food grade

1.2 preparation of raw materials

fresh pineapple is washed with tap water after cutting off the terminal buds, soaked and disinfected in a disinfectant containing 200mg/l effective chlorine (adjust the pH to 6.5 with citric acid) for 5 minutes, dried, remove the skin and eyes with a sharp stainless steel cylinder (with a diameter of 8cm) peeler, cut a round piece with a thickness of about 2.5 cm horizontally with a stainless steel knife, remove the center, and then cut the round piece into 4 parts. Soak the fresh pineapple fan slices in the treatment solution for 3 minutes, remove and dry the surface treatment solution, and then put them on the foam tray (12cm × 12cm × 2cm), 5 pieces (about 120g) per plate, wrapped and sealed with PVC film (0.03mm thick). The water for dissolving chemical reagents is filtered drinking water at about 10 ℃, with a solid-liquid ratio of 1:5. For each treatment of 6 discs, 3 discs were measured on the first day and 3 discs on the seventh day

1.3 experimental design and statistical analysis

the L8 (27) orthogonal design table was used for the test. The test factors were sodium isoascorbate, citric acid, sodium hexametaphosphate, EDTA and calcium chloride. The test levels were 0% and 0.5%. See table I for the test treatment. "1" in the factor column in the table represents the 0% level, "2" represents the 0.5% level. All data were statistically analyzed by minitab14.12 statistical software

1.4 color determination

the l*, a* and b* values of samples with different treatments are measured by the reflection method by the full-automatic colorimeter (rc-300, produced by Minolta company in Japan). Measure 15 times for each treatment and take the average value. L* equal to 100 indicates white, and equal to 0 indicates black; A* when it is positive, it represents red, and when it is negative, it represents green; B* represents yellow when it is positive, and blue when it is negative

1.5 hardness Chinese enterprises are talented enough to produce their own plastic extrusion machinery. They found that their own plastic extrusion machinery is used to determine the hardness of the samples after color determination. The hardness of the samples is measured by ta-xt2 texture analyzer (produced by stable micro systems in the UK) TPA (texture profile analysis): the maximum pressure required for the cylindrical measuring head with a straight diameter of 35mm to vertically crush the cross section of fresh cut pineapple represents the hardness of pineapple slices, and the measurement is repeated 15 times for each treatment, Take the average value

2 results and discussion

table I shows the color and hardness data of fresh cut pineapple treated with different orthogonal combinations of sodium isoascorbate, citric acid, sodium hexametaphosphate, EDTA and calcium chloride on the first day (i.e. the second day of the test) and the seventh day of storage. Since the purpose of this experiment is to screen the factors that have an important impact on maintaining the color and hardness of fresh cut pineapple, the experiment does not consider interaction and does not set repetition. The remaining two empty columns after five factors are arranged by L8 (27) orthogonal table as errors for variance analysis. Table II shows the ranking and ANOVA results of the effects of different treatment factors on the color and hardness of fresh cut pineapple (there are 8 ANOVA tables for all results, which are not listed)

table I orthogonal test combination and test results

treatment secacacl2nahmpedtal*a*b* hardness (n) 1d7d1d7d1d7d1d7d 7263.. 442.5334.0926.0155.8152.. 4664.. 622.4034.6925.8355.7751.. 6664.. 512.3234.5226.0756.0552.. 0964.. 742.0835.1 this scheme does not require customers to modify the product structure and mold structure 226.5857.4752.94521

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