WO2012079224A1

WO2012079224A1 - Processing method for preventing chestnut from browning

Info

Publication number: WO2012079224A1
Application number: PCT/CN2010/079762
Authority: WO
Inventors: 李喜宏; 王雨; 邢亚阁; 李丽; 刘海东; 邵重晓; 李秀琴; 陆书来; 丁玉龙; 曹定爱
Original assignee: 天津科技大学; 内蒙古盛世宏阳农业发展有限公司; 天津绿加粮油科技有限公司; 天津农科食品生物科技有限公司
Priority date: 2010-12-14
Filing date: 2010-12-14
Publication date: 2012-06-21
Also published as: JP2014503203A; JP5723021B2

Abstract

A processing method for preventing chestnut from browning is disclosed herein. The method includes following steps: sieving; treating under low temperature; treating with CO₂ by keeping the chestnut in the environment of CO₂ 5-30%(volume),10-20℃ and relative humidity 85-95% for 2-20 days; smoking chestnut with ethylene or ethanol; removing shell and red skin; deactivating of enzyme by putting the chestnut kernel in the 80-100℃ food grade acidic liquid or 100-110℃ food grade acidic steam for 5-20 minutes and controlling pH of the liquid or steam at1-6, solidifying by putting the kernel in food grade basic liquid of pH 7-12 under 90-100℃ for 5-20 minutes; packing and sealing; sterilizing under high temperature, high pressure and counter pressure; cooling to normal temperature and storing.

Description

Chestnut anti-browning processing method

Technical field

The invention relates to the technical field of food processing, in particular to a method for processing chestnut anti-browning. Background technique

Chestnut is one of China's specialty dried fruits, especially the chestnut in northern China. Its color, aroma, taste and shape are very good. It has a high market share in Japan and South Korea, and its demand is increasing year by year. According to statistics, the annual global production of chestnut is about 70-800,000 tons. The annual output of Chinese chestnut accounts for about 60% of the global chestnut output. The annual demand for chestnuts in the world is over 2 million tons. . Since the overall output of Chinese chestnut is still far from sufficient, the markets in Western Europe and North America have hardly been developed, so its market prospects are very broad.

However, the chestnut processing process is extremely easy to brown. At present, the chestnut kernels in the vacuum or inflated small package on the market are all dark brown, the appearance of the product is poor, and the browning leads to a decrease in the biological effectiveness such as nutrient loss and antioxidant.

Browning of chestnuts includes enzymatic browning and non-enzymatic browning. Enzymatic browning is a color change caused by the oxidation of phenols and tannins in chestnut caused by polyphenol oxidase (PPO) and peroxidase (POD). The product is a complex polymer--black fine. Non-enzymatic browning is mainly the Mai Hard reaction, ascorbic acid oxidation and browning due to metal ions.

In recent years, researchers have studied the control of chestnut browning mainly by using a color protection liquid to prevent browning. The color protection liquid formula is mainly composed of sulfur-containing formula, and the formulation of non-sulfur color protection liquid is rare. Due to the potential harm of sulfur-containing substances to human body, countries around the world have gradually restricted the use of sulfur-containing color protection liquid formulations. Non-sulfur and safe color protection liquid formulations have become a trend. To this end, the Chinese invention patent CN101406212A discloses a method for controlling the browning of the chestnut, and the peeled chestnut is put into the prepared non-sulfur color protection liquid, and the color protection liquid is tea polyphenol, kojic acid, L. - Glutinous gluten or L-tartaric acid, or all combinations of the above; After soaking, rinse off the color of the chestnut surface with water.

Although the above method does not contain sulfur, the coloring solution has the following disadvantages:

(1) When the high temperature sterilization is not carried out, the shelf life of the chestnut processed by the method is not more than 3 to 5 days. When the temperature is completely sterilized at 121 ° C for 30 minutes, the browning is still serious and cannot maintain the true color; (2) the processed chestnut The flavor of the product deteriorates and the unique aroma and taste of the chestnut are lost. Summary of the invention

The technical problem to be solved by the present invention is to provide a natural chestnut anti-browning processing technique which can prevent browning of the chestnut, maintain its golden yellow primary color, and maintain the original flavor of the chestnut and the sweet taste of the chestnut.

To this end, the technical solution of the present invention is as follows:

An anti-browning processing technology for chestnut includes the following steps:

1) Screening of chestnut: Choose full, fully ripe fruit of the flesh to remove various impurities; 2) Low temperature treatment: Under the relative humidity of 80%~95%, the temperature of the control chestnut drops by 1~2 °C every day, and the temperature of the chestnut drops to o~rc;

3) C0 ₂ treatment: Place the chestnut treated in step 2) in an environment where the concentration of C0 ₂ is 5%~30% (volume percentage), the temperature is 10~20 V, and the relative humidity is 85%~95%. The time is 2 ~20 days;

4) Gas fumigation treatment: The chestnut treated by the step 3) is fumigated by one or two kinds of ethylene and ethanol, wherein the ethylene concentration is 0.5~1.5mg/kg, the ethanol is 5%~10%, the temperature is 15~25°C, relative humidity 85%~95%, when ethanol or ethylene is used alone, the fumigation treatment time is 1~4 days; when mixed, the concentration is the same as when used alone, but the fumigation treatment time is 1~ 2 days;

5) remove the shell, go to the red coat, and get the chestnut kernel;

6) Enzymatic treatment: The chestnut kernel is placed in an acidic food slurry or a food grade acidic liquid at 80-100 ° C, or placed in a food grade acidic steam at 100-110 ° C to control the pH of the liquid or steam. 1~6, processing time is 5~20min;

7) curing treatment: at 90~100 °C, the chestnut kernel treated in step 6) is placed in a food grade alkaline liquid with a pH of 7~12, and treated for 5~20min;

8) Bagging and sealing;

9) High temperature, high pressure, back pressure sterilization: sterilization at a temperature of 115~130 ° C, pressure l~2kg/cm ² for 10~40min;

10) Store under cooling and room temperature.

Preferably, the concentration of C0 _{2 in} step 3) is 10% to 15% (volume percentage), and the treatment time is not more than 8 to 10 days.

Preferably, when the ethanol or ethylene is used alone in step 4), the gas fumigation time is 2 days.

Preferably, prior to step 6), the step of repairing, polishing, and removing the pests of the fruit is also included.

In the above method, the acidic food slurry is an aqueous solution of an agricultural product or a vegetable slurry, and the food-grade acidic liquid is an aqueous solution of an inorganic or organic acidic substance or an aqueous solution containing an acidic substance produced by microbial metabolism.

Preferably, the pH of the bactericidal treatment in step 6) is 3 to 5, and the time is 6 to 10 minutes.

In the above method, the food-grade alkaline liquid described in the step 7) is an aqueous solution of an inorganic or organic alkaline substance, and the pH of the curing treatment is 8 to 9, and the time is 6 to 10 minutes.

The processing method of the invention regulates the color, the aroma and the taste of the fruit to the optimum value by the low temperature treatment of the chestnut, thereby promoting the saccharification of the fruit by treating the fruit with C0 ₂ ; Ethanol fumigation of chestnut not only improves the saccharification of chestnut and the scent of chestnut, but also prevents browning during chestnut processing. The chestnut kernel processed by the method of the invention retains its characteristic grain aroma while maintaining the true color of the chestnut It is sweet and delicious, so it is good in color, fragrance and taste. detailed description

The processing method of the present invention will be described in detail below.

The chestnut anti-browning processing method of the present invention comprises the following steps:

(1) Screening of chestnuts. Choose fruits with high sugar and starch content, full and mature flesh, remove disease, insects, mildew, and fruit, classify and remove various impurities.

(2) Low temperature treatment of the screened chestnut: The temperature of the chestnut is controlled to decrease by 1~2 °C every day, and the chestnut temperature drops to 0~rC for long-term storage, and the relative humidity of the environment is always controlled to be 80%~95%.

(3) C0 ₂ treatment of the chestnut after the step (2) treatment: C0 ₂ treatment concentration 5%~30% (volume percentage, the same below), temperature 10~20 °C, relative humidity 85%~95%, time 2~20 days. Among the above conditions, it is preferred that the C0 ₂ concentration is 10% to 15%, and the treatment time is not more than 8 to 10 days, for example, at 20 ° C, for a concentration of 15% of C0 ₂ , the treatment time is not more than 8 days. The concentration of C0 ₂ is 10%, and the treatment time is no more than 10 days.

(4) Gas fumigation treatment: The chestnut treated by the step 3) is fumigated by one or two kinds of ethylene and ethanol, wherein the ethylene concentration is 0.5 1.5 mg/kg, the ethanol is 5% to 10%, and the temperature is 15 ~25°C, relative humidity 85%~90%, when ethylene and ethanol are used alone, the treatment time is 1-4 days, and the optimal treatment time is 2 days. When ethylene and ethanol are mixed, the concentration is used alone. The same, however, processing time is 1 to 2 days.

Fumigation treatment is beneficial to improve the flavor of the chestnut and prevent the browning of the pulp. Fumigation treatment not only improves the saccharification degree of chestnut, improves the flavor of fruit valley, but also prevents enzymatic and non-enzymatic browning during processing.

Preferably, when the ethylene concentration is 1 mg/kg and the ethanol concentration is 8% (volume percentage), the treatment effect is best when fumigation is carried out for 1 day at a temperature of 20 ° C and a relative humidity of 90%.

When the ethylene gas is separately fumigated, it is preferred that the ethylene concentration is lmg/kg, the temperature is 20 ° C, the relative humidity is 90%, and the treatment time is 2 days.

When fumigation with ethanol gas alone, it is preferred that: ethanol 6%, temperature 20 ° C, relative humidity 90%, and treatment time 2 days.

(5) Shelling, removing red, getting chestnut kernels, and shaping it to improve its quality and color. It can be mechanically or manually when it is shelled or red. After shelling and red dressing, it is best to freeze at -1~0 °C for a short period of time or -20~ -10 °C for long-term freezing. Among them, the quality is better at -18~-15°C.

The shaping treatment includes fruit damage repair, polishing and grooving, and removal of pests and diseases. It can be done by hand or mechanical shaping. If it is a low-temperature plastic treatment, the fruit of the shell and the red dress will be damaged and repaired, the pests and flesh will be removed, and then frozen to -18~-20 °C, and then polished and polished to form a groove.

(6) Killing enzyme: The chestnut kernel is placed in a food grade acidic liquid of 80~100°C or food grade acidic steam of 100~110°C, and the pH value of the liquid or steam is controlled to be 1~6, according to the pH value. , depends on the length of the high temperature treatment, the general processing time is 2 ~ 20min. It is preferably treated at a high temperature for 6 to 10 minutes at a pH of 3 to 5. The food grade acidic liquid is an aqueous solution of an agricultural product or a plant slurry, an aqueous solution of an inorganic or organic acidic substance, or an aqueous solution containing an acidic substance produced by microbial metabolism. For example, it may be an agricultural product, a fresh juice of a plant, an aqueous solution of a leaching juice, an aqueous solution containing the slurry or the granules thereof, or an aqueous solution of a lactic acid solution or other inorganic or organic acidic substances.

(7) Curing: The chestnut kernel treated in step 6) is placed in a food grade alkaline liquid with a pH of 7~12 at 90~100 °C for 2~10min. It is preferably treated at a pH of 8 to 9 for 6 to 10 minutes. It is best to wash with drinking water after curing.

The food grade alkaline liquid may be an aqueous solution of sodium hydrogencarbonate or calcium hydrogencarbonate, or may be an aqueous solution of a basic substance such as a carboxylate, an amine (such as triethylamine, piperidine), pyridine or quinoline, or It is an aqueous solution of other agricultural products, plants and other alkaline substances, as long as the pH of the solution is 8-9.

(8) Bagging: It can be used in aluminum foil bags or conventional high-temperature cooking bags, and can be packed in N ₂ or vacuum.

(9) High temperature, high pressure, back pressure sterilization: Sterilize for 10 to 40 minutes at a temperature of 115 to 130 ° C and a pressure of 1 to 2 kg/cm ² . The preferred temperature is 120 to 125 ° C, and the more preferred temperature is 121 ° C.

After the chestnut kernel treated by the above method is cooled to normal temperature, it can be kept at room temperature for more than 12 months.

Claims

Claim

1. A chestnut anti-browning processing technique, comprising the following steps:

1) Screening of chestnut: Choose full, fully ripe fruit of the flesh to remove various impurities;

2) Low temperature treatment: Under the relative humidity of 80%~95%, the temperature of the control chestnut drops by 1~2°C every day, until the temperature of the chestnut drops to o~rc, and keeps it at this temperature;

3) C0 ₂ treatment: Place the chestnut treated in step 2) in an environment where the concentration of C0 ₂ is 5%~30% (volume percentage), the temperature is 10~20°C, and the relative humidity is 85%~95%. For 2 to 20 days;

4) Gas fumigation treatment: The chestnut treated by the step 3) is fumigated by one or two kinds of ethylene and ethanol, wherein the ethylene concentration is 0.5~1.5mg/kg, the ethanol is 5%~10%, the temperature is 15~25 °C, relative humidity 85%~95%, when ethanol or ethylene is used alone, the fumigation treatment time is 1~4 days; when mixed, the concentration is the same as when used alone, the treatment time is 1~2 days;

5) remove the shell, go to the red coat, and get the chestnut kernel;

6) Enzymatic treatment: The chestnut kernel in step 5) is placed in an acidic food slurry or a food grade acidic liquid at 80-100 ° C or placed in a food grade acidic steam at 100-110 ° C to control the liquid or The pH of the steam is 1~6, and the treatment time is 5~20min;

7) Curing treatment: The chestnut kernel treated in step 6) is placed in a food grade alkaline liquid having a pH of 7-12 at 90~100 ° C, and the treatment time is 5-20 min;

8) Bagging and sealing;

10) Store under cooling and room temperature.

2. The chestnut anti-browning processing technique according to claim 1, wherein: the concentration of C0 ₂ in step 3) is 10% to 15% (volume percentage), and the treatment time is 8 to 10 days.

3. The chestnut anti-browning processing technique according to claim 1, wherein: in step 4), when ethanol or ethylene is used alone, the fumigation treatment time is 2 days.

4. The chestnut anti-browning processing technology according to claim 1, wherein: step 5) after the shell is removed and the red dress is removed, the chestnut kernel is refrigerated at -1 to 0 ° C or -20 to -10 °. C frozen.

The chestnut anti-browning processing technique according to claim 1, characterized in that: before the step 6), the step of repairing, polishing and removing the fruit pulp of the fruit is further included.

6. The chestnut anti-browning processing technique according to claim 1, wherein: the acidic food of step 6) The slurry is an aqueous solution of an agricultural product or a vegetable slurry which is an aqueous solution of an inorganic or organic acidic substance or an aqueous solution containing an acidic substance produced by microbial metabolism.

The chestnut anti-browning processing technology according to claim 1 or 6, wherein the pH of the bactericidal treatment in step 6) is 3 to 5, and the treatment time is 6 to 10 minutes.

The chestnut anti-browning processing technique according to claim 1, wherein the food-grade alkaline liquid described in the step 7) is an aqueous solution of an inorganic or organic alkaline substance.

The chestnut anti-browning processing technology according to claim 1 or 7, wherein the curing step in step 7) has a pH of 8 to 9 and a treatment time of 6 to 10 minutes.

10. The chestnut anti-browning processing technology according to claim 1, wherein: in the step 8), the packaging bag used in bagging is an aluminum foil bag or a conventional high-temperature retort pouch, and is packaged in N ₂ or vacuum.