Method for inhibiting yellowing of fresh-cut water chestnuts and keeping quality of fresh-cut water chestnuts

Abstract

The invention discloses a method for inhibiting yellowing of fresh-cut water chestnuts and keeping the quality of the fresh-cut water chestnuts. The method comprises the following steps: (1) cleaning the water chestnuts, and peeling the cleaned water chestnuts; and (2) soaking the freshly cut water chestnuts in distilled water, sterilizing and disinfecting, taking out and draining, soaking in 0.1% or more diallyl trisulfide aqueous solution for 1 hour, taking out and draining, and storing at 1-4 DEG C. The technical operation is simple, and only 0.1% or more diallyl trisulfide aqueous solution is needed to soak for 1 hour; diallyl trisulfide is non-toxic and residue-free, so that food safety problems cannot be caused; raw material consumption is low, and cost is low; the method has a good effect and can inhibit yellowing of the fresh-cut water chestnuts and keep the quality of the fresh-cut water chestnuts for 12 days or above.

Description

Technical Field

[0001] The present invention relates to the technical field of fruit and vegetable preservation, and particularly to a method for inhibiting the yellowing of freshly peeled water chestnuts and maintaining their quality with diallyl trisulfide. Background Art

[0002] Water chestnuts, also known as horseshoes, are rich in carbohydrates, vitamins and minerals, and are a kind of medicinal and edible agricultural product deeply loved by the public. Water chestnuts grow in farmland, and a large number of pathogenic bacteria adhere to their epidermis. Peeling and eating them tastes sweet, safe and healthy. At present, freshly peeled water chestnuts are the main edible form of water chestnuts, but the surface of freshly peeled water chestnuts quickly turns yellow, and this phenomenon is called yellowing (originally this phenomenon was called browning). Yellowing reduces the sensory quality and edible quality of freshly peeled water chestnuts, shortens the storage period, and is an important problem that needs to be solved urgently.

[0003] Xiao Lizhi et al. used 1.5% sodium diacetate combined with heat treatment at 55°C to inhibit the browning of freshly cut water chestnuts. Soaking freshly cut water chestnuts in a high concentration of sodium diacetate made them sour, reducing the edible quality of freshly cut water chestnuts (Xiao Lizhi. Effect of preservation liquid combined with heat treatment on the quality of freshly cut water chestnuts during cold storage [J]. Cereal and Food Industry, 2017, 24(1): 44-52.). Wang Jinxin et al. soaked and treated freshly cut water chestnuts with a composite preservation liquid composed of 80 g / L of table salt + 3 g / L of white sugar + 100 g / L of white vinegar, which could inhibit enzymatic browning and extend its storage period by 6 days. 100 g / L of white vinegar made freshly cut water chestnuts very sour, reducing the edible quality of freshly cut water chestnuts (Wang Jinxin, Yang Fuxin, Si Wanfang. Preservation effect of composite preservation liquid on freshly cut water chestnuts [J]. Food & Machinery, 2018, 34(12): 129-34.). Wang Yuan et al. treated freshly cut water chestnuts with a composite color protection agent composed of 0.2% L-cys + 0.6% CA + 0.6% Vc to inhibit enzymatic browning. 0.6% acetic acid made freshly cut water chestnuts very sour, reducing the edible quality of freshly cut water chestnuts (Wang Yuan. Inhibition of browning of freshly cut water chestnuts by composite color protection treatment [J]. Food Safety Guide, 2013, (4): 76-8.). Deng Jing et al. treated freshly cut water chestnuts with magnesium hypochlorite basic. Magnesium hypochlorite basic belongs to a chemical preservative and has residues in freshly cut water chestnuts, which will cause food safety problems (Deng Jing, Wang Jianhui, Li Wen, etc. Study on the color protection and preservation effect of magnesium hypochlorite basic on freshly cut water chestnuts [J]. Packaging Engineering, 2016, 5(3): 20-3.). Qiu Songshan et al. used chitosan / nano-TiO 2 composite coating to treat freshly cut water chestnuts, but did not obtain the specific number of days to extend the storage period (Xing Yage, Qiu Songshan, Li Xihong, etc. Chitosan-nano-TiO 2Study on the Preservation Effect of Composite Coating Films on Fresh-Cut Water Chestnuts [J]. Food and Fermentation Industries, 2008, 34: 149-51.). Peng Litao et al. treated fresh-cut water chestnuts with 0.5%-2% chitosan coating, but did not obtain the specific number of days for extending the storage period (Peng Litao, Jiang Yueming, Yang Shuzhen, et al. Inhibition of Browning of Fresh-Cut Water Chestnuts by Chitosan Coating [J]. Plant Physiology Communications, 2002, 38(6): 554-6.). Peng Yong et al. treated fresh-cut water chestnuts with two kinds of films, chitosan and sodium alginate, but did not obtain the specific number of days for extending the storage period (Peng Yong, Li Yunfei. Effects of Chitosan and Sodium Alginate Coatings on Browning, Rot and Quality of Fresh-Cut Water Chestnuts [J]. Science and Technology of Food Industry, 2013, 34(17): 334-41.). Xu Tingqiao et al. treated fresh-cut water chestnuts with nano-SiOx / chitosan composite coating, but did not obtain the specific number of days for extending the storage period (Xu Tingqiao, Luo Zisheng, Xie Jing. Effects of Nano-SiOx-Chitosan Composite on the Quality and Physiology of Fresh-Cut Water Chestnuts [J]. Journal of Chinese Institute of Food Science and Technology, 2011, 11(4): 123-8.). Hou Chuanwei et al. treated fresh-cut water chestnuts with a composite color protection agent (0.2% phytic acid + 0.1% L-cysteine + 0.25% zinc acetate + 1% sodium diacetate). 0.25% zinc acetate and 1% sodium diacetate would make fresh-cut water chestnuts very sour, reducing the edible quality of fresh-cut water chestnuts. Zinc acetate and sodium diacetate belong to chemical preservatives and have residues in fresh-cut water chestnuts, which will cause food safety problems. Hou Chuanwei et al. used a composite sulfur-free color protection agent (optimal formula (mass fraction): 0.25% L-cysteine + 0.8% sodium chloride + 0.6% citric acid + 1.0% sodium pyrophosphate) to protect the color of fresh-cut water chestnuts. 0.6% citric acid would make fresh-cut water chestnuts very sour, reducing the edible quality of fresh-cut water chestnuts. Sodium pyrophosphate belongs to chemical preservatives and has residues in fresh-cut water chestnuts, which will cause food safety problems (Hou Chuanwei, Wei Shuxin, Wang Anjian. Development of a Composite Preservative for Fresh-Cut Water Chestnuts [J]. Food Science and Technology, 2007, 12: 195-7.). Deng Yuanxi et al. (Deng Yuanxi, Chen Jia, Wu Jie, et al. Optimization of Sulfur-Free Color Protection Agent Formula for Fresh-Cut Water Chestnuts by Response Surface Methodology [J]. Food Industry, 2018, 39: 126-31.). Zeng Kaifang et al. used heat treatment to protect the color of fresh-cut water chestnuts, but did not obtain the specific number of days for extending the storage period, and heat treatment would cause more water loss in water chestnuts and a significant decline in edible quality (Zeng Kaifang, Tian Weina, Ming Jian. Study on the Effects of Heat Treatment on the Quality of Fresh-Cut Water Chestnuts by Response Surface Methodology [J]. Science and Technology of Food Industry, 2010, 31(2): 70-6.). Jiang Yue et al. used 40% ethanol to inhibit the browning of fresh-cut water chestnuts, and 40% ethanol would make fresh-cut water chestnuts have a strong alcoholic smell, which is unacceptable (Jiang Yue, He Fengping, Zhong Huiling, et al. Effects of Ethanol Treatment on Yellowing and Related Enzymes of Fresh-Cut Water Chestnuts [J]. Science and Technology of Food Industry, 2017, 38(10): 326-30.).Fan Chuanhui et al. treated fresh-cut water chestnuts with 55% ethanol, but did not obtain the specific number of days for extending the storage period. Moreover, 55% ethanol would make the fresh-cut water chestnuts have a strong wine smell, which was unacceptable (Fan Chuanhui, Chen Xueling, Wang Shaohua, et al. Effects of ethanol soaking on the storage quality changes of fresh-cut water chestnuts [J]. Modern Food Science and Technology, 2018, 34(12): 122-128.). Deng Lili et al. fumigated fresh-cut water chestnuts with acetaldehyde, but did not obtain the specific number of days for extending the storage period. Acetaldehyde belongs to chemical preservatives and has residues in fresh-cut water chestnuts, which will cause food safety problems (Deng Lili, Ming Jian, Tian Weina, et al. Effects of acetaldehyde fumigation treatment on the quality changes of fresh-cut water chestnuts [J]. Food Science, 2010, 31(2): 233-236.). Wang Haiping et al. soaked water chestnuts in a mixed solution composed of NaCl, citric acid and Vc for 15 minutes, which could protect the color of water chestnuts, but did not obtain how long the color could be protected. Citric acid would make the water chestnuts sour and inedible (Wang Haiping, Huang Hesheng, Tian Qing. Optimization of sulfur-free color protection conditions and storage quality research of fresh-cut water chestnuts [J]. Food Science and Technology, 2019, 2019(44): 6.). Niu Lifang et al. treated water chestnuts with ultraviolet rays and ethanol, which could reduce their browning. The combined treatment of ultraviolet rays and ethanol had a better effect, but did not obtain the specific number of days for extending the storage period. Moreover, ultraviolet rays required special equipment and had a high cost, and ethanol made the water chestnuts have a wine smell and the edible quality decreased (Niu Lifang, Yang Ying, Yi Yang, et al. Effects of ultraviolet irradiation and ethanol treatment on the browning of fresh-cut water chestnuts [J]. Food Science and Technology, 2019, 44(11): 6.).

[0004] Inhibiting the yellowing of freshly peeled water chestnuts by diallyl trisulfide and maintaining their quality is a biotechnology, which will not cause food safety problems and will not reduce the edible quality. At present, there is no report at home and abroad on inhibiting the yellowing of freshly peeled water chestnuts by diallyl trisulfide and maintaining their quality. Summary of the Invention

[0005] The object of the present invention is to overcome the above defects of the prior art and provide a method for inhibiting the yellowing of freshly peeled water chestnuts by diallyl trisulfide, which is efficient, safe, does not reduce the edible quality, is simple to operate and has low cost.

[0006] To achieve the above object, the present invention provides a method for inhibiting the yellowing of freshly peeled water chestnuts by diallyl trisulfide, which is characterized by including the following steps:

[0007] (1) Wash, peel, remove the roots and buds of the water chestnuts;

[0008] (2) Soak the freshly peeled water chestnuts obtained in step (1) in distilled water for sterilization and disinfection, take them out and drain the water, soak them in an aqueous solution of diallyl trisulfide, take them out and drain the water, and store them.

[0009] Preferably, the fresh peeled water chestnuts in step (1) are the white bulbs after the water chestnuts are peeled and the roots and buds are removed; the soaking in distilled water in step (2) means that the fresh peeled water chestnuts are completely submerged in distilled water, the sterilization and disinfection means ozone sterilization and disinfection treatment for 30 minutes, the water draining time is 10 minutes each, the soaking in diallyl trisulfide aqueous solution means soaking in diallyl trisulfide aqueous solution with a mass percentage concentration of 0.1% or more for 1 hour, and the storage is carried out at 1-4°C.

[0010] The beneficial effects of the present invention are as follows: ① The technical operation is simple, only need to soak the fresh peeled water chestnuts in diallyl trisulfide aqueous solution with a mass percentage concentration of 0.1% or more for 1 hour; ② Diallyl trisulfide will not cause food safety problems; ③ The raw material dosage is small and the cost is low; ④ The effect is good, and it can inhibit the yellowing of fresh peeled water chestnuts for 12 days or more. Specific embodiments

[0011] The technical solution of the present invention will be described in detail below in conjunction with embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Without departing from the spirit and essence of the present invention, any modification or replacement of the steps or conditions of the present invention belongs to the scope of the present invention.

[0012] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0013] In this embodiment, the degree of yellowing is measured and calculated by the area method: the percentage of the yellowing area of the fresh peeled water chestnuts in the total area of the contact surface with air. If there is no yellowing on the contact surface of the fresh peeled water chestnuts with air, the degree of yellowing is 0. When the contact surface of the fresh peeled water chestnuts with air is completely yellowed, that is, completely yellowed, the degree of yellowing is 100%. The storage time when the treated sample is completely yellowed minus the storage time when the control sample is completely yellowed is the number of days that the treatment method inhibits the yellowing of fresh peeled water chestnuts.

[0014] (1) Sample treatment

[0015] Select fresh water chestnuts without rot, breakage, damage and with basically the same size, wash them with tap water, peel them with a peeling knife, and remove the roots and buds. Soak the fresh peeled water chestnuts in distilled water, and the distilled water should completely submerge the fresh peeled water chestnuts. Sterilize and disinfect them with ozone for 30 minutes, take out the fresh peeled water chestnuts and drain them for 10 minutes. Every 100±10 g of fresh peeled water chestnuts is used as a sample, soak it in 1±0.01 liter of diallyl trisulfide aqueous solution with a mass percentage concentration of 0.1% or more for 1 hour, take it out and drain it for 10 minutes, put it in 1 fresh-keeping box, and store it at 1-4°C. Measure and calculate the degree of yellowing every 3 days. Take the one without soaking treatment with diallyl trisulfide aqueous solution as the control.

[0016] (2) Experimental results

[0017] The control sample was completely yellowed on the 12th day, the sample treated with 0.1% aqueous solution of diallyl trisulfide was completely yellowed on the 24th day, and the samples treated with aqueous solution of diallyl trisulfide above 0.1% were gradually yellowed respectively after the 24th day.

[0018] It can be seen that in this embodiment, the effect of inhibiting the yellowing of freshly peeled water chestnuts with diallyl trisulfide is very good, and the aqueous solution of dithiothreitol at 0.1% and above can inhibit the yellowing of freshly peeled water chestnuts for 12 days and above.

Claims

1. A method for inhibiting yellowing of freshly peeled water chestnuts and maintaining their quality, characterized in that The steps are as follows: soak every 100±10g of freshly peeled water chestnuts in 1±0.01 liter of 0.1% or above diallyl trisulfide aqueous solution for 1 hour.