Research progress on avocado processing technology

1 Avocado processing status

1.1 International processing

Avocado nuts have a high oil content of 8% to 29%. They are used as food in tropical America, and avocados are regarded as fruit treasures in European and American countries. In addition, more than 80% of the avocado fat is an unsaturated fatty acid, which is easily digested and absorbed by the body, and can also remove cholesterol from the blood. In addition, avocado fatty acids have strong skin permeability and good sunscreen effect, and are high-quality cosmetic raw materials. The United States, Japan and other countries are at the forefront of the research and development of avocado, and there are thousands of toiletries produced by avocado, including cleansers, creams, masks, soaps, shampoos, sunscreens, etc.

Therefore, the economic benefits of the avocado-related industrial chain are relatively high. In 2004, the export market price of Mexican avocado was US$1,555/t. In 2008, the export price rose to US$2,130/t. In recent years, the countries of the Americas have attached great importance to the cultivation of avocado. Avocado producers are very fond of eating avocados, such as Israelis who regard avocado as one of the daily essential foods; Mexican per capita avocado consumption of more than 8 kg per year.

1.2 Domestic processing

China has insufficient understanding of avocado, insufficient funding and propaganda, and the research and promotion of avocado has been slow, resulting in the production of avocado in China far from meeting domestic demand, mainly relying on large imports from Mexico.

At present, China’s rare large-scale avocado plantations have less avocado production. Most of the avocados are sold only as fruits, and a small part is used for processing and manufacturing products, mainly in the fields of cosmetics, western food, and shea butter. The advantage of China’s avocado manufacturing products is far less than that of developed countries, and the economic benefits are low. At the same time, the domestic avocado fruit or processed products are relatively expensive, and consumers do not know enough about the comprehensive value of avocado, so the sales are not smooth.

2 Avocado Processing Technology

2.1 Avocado Oil

Avocado oil content is 15%~30%. It mainly contains fatty acids such as oleic acid, linoleic acid, palmitic acid, palmitic acid and stearic acid. Its color is dark green and can be used in the cosmetics industry or after processing. The extraction of avocado oil is divided into two methods, press and centrifugal separation, which are best by centrifugal separation. Avocado oil contains a large amount of monounsaturated acid (oleic acid), contains no cholesterol, can be eaten with any food, and has high nutritional value. Compared to corn oil, almond oil and olive oil, avocado oil has the strongest penetration into the skin and can deliver beneficial compounds into the skin’s epidermis, even in the dermis. At present, there are 240 kinds of toiletries for adding avocado oil in the United States, and the addition ratio ranges from 0.1% to 50.0%.

2.2 Food aspects

Avocado is also widely used in the food industry. It is rich in various physiological and physiological activities such as oil, vitamins, minerals, protein, sugar, etc., and is widely recognized for its high energy, low sugar and easy digestion. Consumers favor. The avocado has a high oil content and is slippery like butter. It is called “avocado” and is known as “the cream of the poor” in Mexico and other places.

In addition to raw food, avocado can also be made into sushi, salad, salad, juice, jam, fruit and so on. The famous tourist resort of Canary Islands has dozens of avocado-related food formulas, including 5 salads, 12 kinds of pureed vegetables and jams, and 16 kinds of dishes. There are as many as 53 recipes for guacamoli butter. South Africa uses avocado pulp as a baby food. Some people try to mix avocado with cow’s milk, pasteurized and then inoculate lactic acid bacteria to make fermented avocado products, which avoids the bitterness after strong heat treatment, and maintains the original nutrition and flavor of avocado as much as possible.

2.3 Medical aspects

The main component of avocado pulp fat is fatty acid, the most abundant of which is oleic acid, which is a fatty acid that cannot be synthesized and necessary in the human body. It has the function of regulating blood cholesterol and can prevent and treat cholesterol accumulation in blood vessel wall. arteriosclerosis. In addition to oleic acid, avocado is also rich in monounsaturated fatty acids, which function similarly to oleic acid. In addition, avocado also contains a large amount of linoleic acid, which can lower the concentration of “bad cholesterol” in the blood and promote the production of physiologically active substances such as prostaglandins.

Avocado fruit has high energy and low sugar, and the peel can be used for tea drinking, which has certain relief effect on diabetes. According to research conducted by Shizuoka University in Japan, avocado can alleviate liver disease, inhibit the virus that damages liver health, and successfully test it in mice, providing a basis for the development of acupuncture drugs for treating liver diseases. Related tests have proved that skin care products containing purslane and avocado extract can assist in the treatment of various dermatitis diseases such as adipose eczema, atopic dermatitis, facial glucocorticoid-dependent dermatitis, etc., and its curative effect is good and safe.

2.4 Industrial aspects

牛油果种仁富含脂肪，为重要的食用油及工矿用油，又可制人造黄油及肥皂。牛油果油没有刺激性，酸度小，乳化后可长久保存，除食用外，还可用作机械润滑、高级化妆品、皮肤疾病用油及软膏原料。在 2016 年，有人公开了一种利用牛油果制备生物柴油的方法，步骤如下：加入沸石分子筛吸附剂对牛油果油进行预处理，得到纯牛油果油；将纯牛油果油、甲醇和磁性纳米催化剂以重量比为 100.0∶ （ 25.0~50.0 ） ∶（ 0.5~2.0 ）加入反应釜中进行酯化反应；再经过分离生物柴油粗品和提纯，即可得到生物柴油 。如果利用牛油果制备生物柴油试验成功，将为解决当前资源匮乏问题探索出一条新的路径。

Avocado seed kernels are rich in fat and are important edible oils and industrial and mining oils, as well as margarines and soaps. Avocado oil is not irritating, has low acidity, and can be preserved for a long time after emulsification. In addition to food, it can also be used as mechanical lubrication, high-grade cosmetics, skin disease oil and ointment raw materials. In 2016, a method for preparing biodiesel using avocado was disclosed as follows: pretreatment of shea butter with zeolite molecular sieve adsorbent to obtain pure avocado oil; weight ratio of pure avocado oil, methanol and magnetic nanocatalyst 100.0: (25.0~50.0): (0.5~2.0) is added to the reaction kettle for esterification reaction; after the crude biodiesel is separated and purified, biodiesel can be obtained. If the successful preparation of biodiesel from avocado is successful, a new path will be explored to solve the current resource shortage problem.

3 Direction of development

Avocado has wide adaptability, fast growth and high yield. The residents of Guatemala origin are often used for food, so they are known as high-yield crops with fruits, grains and oil. In recent years, the nutritional value and health value of avocados have become more and more familiar, so that their demand is increasing and prices are rising. Most of today’s avocados are eaten as fresh fruit, because the texture of the flesh is too soft to be preserved for a long time, and it is difficult to taste except for the ripening season of avocado. Therefore, the avocado can be made into dried products that can be eaten in other seasons. In addition, the deep processing of avocado is mainly carried out by extracting the fruit oil in avocado for cosmetics processing.