CN101200081A - A kind of anti-low temperature bamboo leaf color preservation treatment method used in food packaging - Google Patents

Abstract

The invention relates to a processing method of color keeping for low temperature resistant bamboo leaves used for food package. The invention is characterized in that: after being preprocessed, the bamboo leaves are marinated in saturated brine; after being rinsed, the bamboo leaves are marinated in alkali liquor for 24 to 36 hours; the bamboo leaves are rinsed by water after being get out and then are put into hot water to be blanched for 10 minutes; the bamboo leaves are put into citric acid with an adjusted pH value 1.5 to be marinated for 80 to 120 hours, and then are rinsed by water quickly and put into color protecting liquid to be marinated for 40 to 48 hours in the temperature of 15 DEG C; after the color is protected, the bamboo leaves are get out and then are marinated in color protecting setting solution for 3 to 5 hours; the bamboo leaves are get out and are boiled in the water for 20 minutes, and then are cooled quickly and are stored for reservation in the temperature of 4 to 11 DEG C. Zongzi wrapped by the bamboo leaves which are processed by the method of the invention can be cold stored for 90 days in the temperature of 5 DEG C below zero and still keep natural green color after being cooked, therefore the invention is helpful to increase the quality and impression of the frozen Zongzi.

Description

A kind of anti-low temperature bamboo leaf color preservation treatment method used in food packaging

technical field

The invention relates to a method for preserving the color of green bamboo leaves used in food packaging with low-temperature resistance, in particular to a method for preserving the natural green color of green bamboo leaves used in food packaging after low-temperature refrigeration.

technical background

my country is known as the "Kingdom of Bamboo". There are more than 40 genera and 400 species of bamboo in the territory, and the area of bamboo forest is about 4 million hectares. Due to its unique biological, ecological and multi-purpose characteristics, bamboo has been paid more and more attention by people, and it is playing an increasingly important role in China's sustainable development strategy. my country is at the international leading level in the research and development of active ingredients of bamboo leaves. Zongzi has a long history. On May 5th of the lunar calendar in 340 BC, Qu Yuan, a patriotic poet and doctor of the Chu State, faced the pain of subjugation, and threw a big stone into the Miluo River in grief. In order to prevent Qu Yuan's body from being eaten by the dragon and water beasts, people used natural bamboo leaves to throw them into the Miluo River. Since then, zongzi has been widely spread among the people as a delicious food with national cultural characteristics. The bamboo leaves used to make zongzi generally refer to zongzi leaves, the scientific name is Indicalamus Leaf, the leaves of the broad-leaved Ruozhu (l. Zongzi is to use its special bamboo fragrance and antiseptic effect. Ruo Ye grows in the vast mountains and mountains, with well-developed root system and strong vitality. It is not only a good soil and water protection vegetation, but also an inexhaustible wealth. It is the "green bank" of the people in mountainous areas. It contains a large amount of chlorophyll and a variety of amino acids that are beneficial to the human body. It can extract natural flavors and fragrances and food additives. It smells aromatic and feels like returning to nature. It can be used not only for making zongzi, but also for packaging other foods, table decorations and food foils, as well as for making utensils, making lunch boxes and cutting them into various shapes. Zong leaves grow naturally, are non-toxic, non-polluting, and can be harvested every year and every season. As food packaging, they are non-polluting and "disposable" for use. Therefore, it is called "natural green food" by today's nutritionists. However, limited by the growing season, people are not satisfied with being able to enjoy zongzi only on May 5th of the lunar calendar every year, and hope that they can be freely purchased in markets such as supermarkets all year round. For this reason, many food processing enterprises produce a large amount of zongzi by batch processing according to market demand, and the zongzi that cannot be sold for a while are preserved in freezer or refrigerator. Since the temperature of the freezer or refrigerator is usually between -25 and 3°C, over time, the color of the zong leaves wrapped in natural bamboo leaves will gradually turn yellow and lose their original green color. Elements, natural fragrance substances, etc. are also damaged due to low temperature. Therefore, the two major problems of color protection and frost resistance of bamboo leaves have become the technical bottleneck of Zongzi production, which has restricted the development of production.

Contents of the invention

The object of the present invention is to provide a kind of low temperature resistant green bamboo leaf color retention method that is suitable for various food packaging and uses low temperature resistant bamboo leaves wrapped in zongzi, and does not affect the natural green color of the leaves after long-term refrigeration.

The present invention is realized through the following technical solutions:

(1) Bamboo leaves are collected and pretreated by decontamination, impurity removal, grading, binding, etc., and then soaked in saturated salt water and stored for processing, so as to ensure the freshness of bamboo leaves.

(2) After rinsing the bamboo leaves soaked in saturated salt water, soak them in 4% Na ₂ CO ₃ lye for 24 to 36 hours. Leaves are beneficial to the production of zongzi.

(3) Take out the bamboo leaves soaked in lye, rinse them with clear water, and put them into 90°C-95°C hot water to blanch for 10 minutes, in order to kill the enzymes in the bamboo leaves.

(4) Soak the blanched bamboo leaves in an acid solution with a pH of 1.5 adjusted with citric acid for 80 to 120 hours. The purpose is to replace the magnesium atoms in the chlorophyll with H+. Acid refers to hydrochloric acid solution.

(5) Take out the bamboo leaves, rinse them quickly with clear water, put them in the pre-prepared color-preserving solution, and soak them for 40-48 hours at a temperature of 15°C to preserve the color.

(6) Take out the bamboo leaves after the color is preserved and soak them in 0.8% calcium chloride, 0.5% Vc solution for 3 to 5 hours.

(7) Take out the bamboo leaves and boil them in water for 20 minutes, then cool them down rapidly and store them at 4°C-11°C for later use.

The compound formula of color retention liquid of the present invention is:

Sodium copper chlorophyllin 700～800mg

Ferrous chloride 500～650mg

Zinc chloride 550～700mg

Deionized softened water 1000ml

The bamboo-leaf-wrapped zongzi treated with the method of the present invention is refrigerated at -15°C for 90 days after being cooked, and still maintains a good natural green color, thereby helping to improve the quality of frozen zongzi and look and feel.

Drawings and Description of Drawings

Fig. 1 is the flow chart of color retention method of the present invention

Detailed ways

The present invention will be further described below in conjunction with the method flow chart.

(1) Take newly harvested fresh bamboo leaves, wash and decontaminate them with clean water, and remove miscellaneous leaves, then classify them according to the size of the bamboo leaves, bundle them into bundles of about 30 pieces, and transfer them to the next step for color retention treatment. If the color-preserving treatment is not carried out immediately, it should be soaked in saturated salt water first, and wait for the color-preserving treatment, so as to ensure the freshness of the bamboo leaves.

(2) Get 30 bundles of bamboo leaves soaked in saturated salt water through rinsing or through the bamboo leaves that have been cleaned in the process (1), soak 30 hours in a ceramic jar with ₄ % Na _CO lye, remove the bamboo leaves The wax on the surface softens the bamboo leaves, which is conducive to the production of zongzi.

(3) Take out all the bamboo leaves, rinse them with clear water, and blanch them in hot water at 90°C-95°C for 10 minutes to kill various active enzymes in the bamboo leaves.

(4) Put the blanched bamboo leaves into an acid solution with a PH value of 1.5 adjusted with citric acid and soak for 100 hours. The purpose is to replace the magnesium atoms in the chlorophyll with H+.

(5) Take out the bamboo leaves, rinse them quickly with clean water, put them in the pre-prepared color protection solution, and soak them for 44 hours at a temperature of 15°C.

(6) Take out the bamboo leaves and soak them in a solution containing 0.8% calcium chloride and 0.5% Vc for 4 hours. The purpose is to make the color-protected bamboo leaves shaped by calcification and antioxidant effects.

(7) Take out the bamboo leaves and boil them in water for 20 minutes, then cool them down rapidly and store them at 4°C-11°C for later use.

Claims (5)

1. a low temperature resistant bamboo leaf color retention treatment method used in food packaging, characterized in that: (1) Bamboo leaves are soaked and stored with saturated salt water after pretreatment; (2) Bamboo leaves are soaked in lye for 24 to 36 hours after rinsing; (3) Take out the bamboo leaves, rinse them with clean water, and put them in hot water for 10 minutes; (4) Put the bamboo leaves into an acid solution with a pH value of 1.5 adjusted with citric acid and soak for 80 to 120 hours; (5) Rinse quickly with clean water, put it in the color protection solution, and soak it for 40-48 hours at a temperature of 15°C; (6) After the color protection is completed, take out the bamboo leaves and soak them in the color protection and shaping solution for 3 to 5 hours; (7) Take out the bamboo leaves and boil them in water for 20 minutes, then cool them down rapidly and store them at 4°C-11°C for later use. 2. the anti-low temperature bamboo leaf color retention treatment method used for food packaging according to claim 1, characterized in that said lye is Na ₂ CO ₃ solution, and its solubility is 4%. 3. The low temperature resistant bamboo leaf color retention treatment method for food packaging according to claim 1, characterized in that the temperature of the hot water during blanching in the hot water is 90°C-95°C. 4. the anti-low temperature bamboo leaf color retention treatment method that food packaging uses according to claim 1 is characterized in that described acidic solution refers to hydrochloric acid solution. 5. the anti-low temperature bamboo leaf color-preserving treatment method that food packaging uses according to claim 1 is characterized in that described color-protecting and setting solution refers to containing 0.8% calcium chloride, 0.5% Vc solution.

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