The so-called jelly, commonly known as fruit jelly, also known as jelly, by the gel agent plus water, sugar, fruit and vegetable juice or fruit pulp and other raw materials, through the dissolution, blending, filling, sterilization, cooling and other processes from the jelly semi-solid health food.

Jelly crystal appearance, bright color, soft and smooth taste, sweet but not greasy, loved by children and female friends. Jelly has become a commonly chosen leisure and convenient food for home travel.

In 2015, China’s jelly industry exceeded 20 billion yuan in size, and has surpassed Japan to become the world’s largest jelly producer and consumer market.

At present, there are more types of health jellies on the market, which can be divided into gel health jellies and suction health jellies according to the organizational form; from the point of view of production raw materials, there are fruits, vegetables, Chinese herbs, teas and so on. Health care jelly has both the freshness and tenderness of jelly, but also with fruits and vegetables, Chinese herbs and other substances of the nutritional health functions, while adding less or no artificial colors, sweeteners and other food additives, sweetness is appropriate, delicate taste, has a broad market prospects.

Health jelly production is the most important raw material is the gel agent, commonly used gel agent konjac gum, xanthan gum, carrageenan, agar, etc., add a single gel agent and compound gel agent, compound gel agent is divided into compound two gel and compound three gel, etc..

Usually, the quality of health jelly prepared by compounding gel agent is better than that of single gel agent in terms of solidification, elasticity and toughness, and the gel type, ratio and addition amount of compounding gel agent have a great influence on the quality of health jelly. This paper reviews the gel agent and production process of health jelly production, and introduces the current research status of vegetable and fruit health jellies to provide reference for the industrial development of health jellies.

Health care jellies of

Single gel agent and compound gel agent

Gelatin is an important raw material for making health jellies, and natural polysaccharide gums, such as konjac flour, xanthan gum, carrageenan, agar, tamarind gum, etc., are often used as the basic gelatin.

Konjac flour, xanthan gum and other natural polysaccharide gum is rich in dietary fiber, with the promotion of gastrointestinal peristalsis, regulation of blood glucose, adsorption of fat, cholesterol and bile acids, the prevention of cardiovascular disease and other effects.

Carrageenan in the oxidative degradation and acid degradation to get carrageenan oligosaccharides, DPPH free radical scavenging as well as reducing ability is very strong, with the role of delayed aging and antioxidant.

Usually health care jelly production are used konjac flour, carrageenan, xanthan gum or agar, etc. Compound into two or three gels, gel types, ratios and additive amount of different gel formed by different properties.

The production of health care jelly on the basic requirements of the gel agent is a gelling agent can be produced after cooling gel, with appropriate hardness and elasticity, and good water retention, smooth taste of a single gel agent on the quality of health care jelly effect is shown in Table 1.

As can be seen from Table 1, a single gelling agent is deficient in gelation, elastic toughness, homogeneity, transparency, texture and organization status.

When using a single gelling agent, carrageenan has a special fishy flavor, low gelling concentration, good toughness, high transparency; sodium alginate has high transparency, but the toughness of the jelly is insufficient; agar coagulation is fast, the texture is homogeneous, but the jelly has a rough texture, is not smooth enough, lacks chewy, elasticity, toughness is poor. Pectin as a gelling agent, the pH value required for solidification is low.

Overall, the gel strength of jelly increased with the increase in the dosage of gelling agent, but the excessive dosage would make the jelly hard, lack of elasticity and poor taste.

The compounding of gelling agents can enhance the synergistic effect between the gels so that the performance of the gelling agents can complement each other, thus obtaining products with better performance. The effects of compounding gelling agents on the quality of jelly are shown in Table 2 and Table 3.

The types, ratios and additive amount of compounding gelling agents have a great influence on the quality of health jellies. Liu Junhong et al. considered the most suitable quality ratio for jelly gelling agent as konjac flour: xanthan gum: carrageenan = 2:3:1 (mass ratio). When the amount of coagulant was 1.0 %, the jelly product had the highest sensory score. When the amount of coagulant < 1.0 > 1.0 %, the appearance was better, but the solidification was too fast resulting in poor tissue state of the jelly.

Zhang Yan used gelatin as a gelatinizing agent to prepare Hynobius serpentis grape health jelly, the product texture is uniform, good transparency, crisp and tough, but the coagulation speed is slow, the amount of gelatin to be added is large, otherwise it is easy to produce delamination phenomenon. And the use of gelatin and agar in the ratio of 5:1 compounding, enhanced the health of the jelly gel and smooth, the jelly produced more full, transparent.

Health jelly production process and key technologies

Raw materials are mostly selected fresh without mold, no insect corrosion, no frostbite or mechanical damage to fruits, vegetables, etc., prepared into fruit and vegetable juice, first of all, will be handled by the gel solution and fruit and vegetable juice mixed well, and then according to the process needs to be added to the appropriate honey, citric acid and other flavoring substances, and sometimes need to be added to the preservatives such as potassium sorbate. Fruit and vegetable juice, gelling agent, sweetener and acidifier is the main factor affecting the quality of jelly.

(1) sweeteners are generally used fruit and vegetable juices of their own sweetness, or add white sugar, brown sugar, honey and so on. In order to enhance the health care of the product, can also be used low energy, anti-caries, improve gastrointestinal function of sorbitol, maltitol, isomalt oligosaccharides as sweeteners, get the product sweetness long and has good health care functions.

(2) Citric acid is mainly used to give the product sour taste, adjust the flavor of the product, and reduce the pH value, inhibit the growth of bacteria, and its dosage has a greater impact on the taste and the stability of gelatin, the dosage is too low to play its proper role, the dosage is too high, the gel agent undergoes hydrolysis, which affects its gel properties. Citric acid is first dissolved with a small amount of water, because it will make the sugar gel pH value lower, affecting the molding of the gel, so it should be added to control the speed and heating time, stirring evenly, to avoid local acidity is too high.

(3) The gelling agent used in the test is generally a compound gel, dissolving the gel cooking process should be constantly stirring to prevent burning, and filtered while hot to remove impurities and the presence of gel particles.

Current status of processing of health jellies

3.1 Vegetable Jelly
Vegetable health jelly is currently the largest number of health jellies in a class, the main materials are ginger, Buddha’s hand melon, bitter melon, okra, enoki mushrooms, kelp, yam, ginger, purple sweet potatoes, carrots and other vegetables, the development of a series of health care vegetable jellies.

Yu Xiaoling and others used purple sweet potato as raw material to produce light red, beautiful appearance, with high nutritional value of purple sweet potato health care jelly. Jia Juan carrot juice as the main raw material, carrageenan, sodium carboxymethylcellulose and agar for the preparation of compound glue with carrot and honey flavor, smooth texture, color and lustre uniformity, moderately sweet and sour carrot and honey nutritional health care jelly.

Vegetable health care jelly carrots, bitter melon, okra and other vegetables in the carotene, bitter melon glycosides – 5 – hydroxytryptophan, a variety of amino acids, vitamins and minerals and other nutrients to be better absorbed and utilized by the human body, giving the jelly a special flavor and rich nutritional value, not only to improve the grade of jelly, but also has a health therapeutic effect.

3.2 Fruit health care jelly
At present, the production scale of fruit health jelly is second only to vegetable health jelly, commonly used fruit raw materials are kiwi, papaya, strawberry, cranberry, mulberry, snow lotus fruit, grapes, guava and so on, by steaming, juice, filtration, composition adjustment, concentration, defoaming, boxed, sealed, sterilized, cooled and other technological processes to develop into fruit health jellies, with a pure color and lustre, fragrant flavor, delicate taste, elasticity and toughness, sweet and sour, tasty. It has pure color, fresh flavor, delicate taste, elasticity and toughness, sweet and sour, and has certain nutritional value and health care value.

At present, China’s fruit planting scale, technology and production have been greatly improved, fruit nutrition is rich, but the fruit origin concentration, storage and preservation technology is not perfect, fresh fruit backlog and decay and other defects constrain the sales of fruit, the development of fruit health care jelly for the development and utilization of fruits to open up new ways.

Tian Long et al. took kiwifruit as the main raw material and used orthogonal test to develop the nutritional and health care kiwifruit jelly with delicate texture, suitable sourness and sweetness, rich in water-soluble polysaccharides and high fiber and low caloric energy. Using vinegar, kiwifruit and apple as raw materials, Xu Qingping developed a vinegar jelly with uniform color, good tissue state and sweet and sour taste.

3.3 Herbal health care jelly
Chinese herbs are the traditional medicine in China, and there is a great deal of potential in the food industry to utilize the valuable resources of Chinese herbs to develop a variety of health food products.

As far as ingredients are concerned, the dosage of herbs has the greatest influence on the taste and color of the product. If the ratio of Chinese herbs is too large, the bitter flavor is heavy, the taste is poor, and it is difficult for consumers to accept; if the ratio is too small, the health value of Chinese herbs is lost.

At present, the preparation of Chinese herbal health care jelly mainly has cassia seed health care jelly, honeysuckle health care jelly, dry lotus herb health care jelly, chrysanthemum health care jelly, poria health care jelly, cordyceps health care jelly, etc., the preparation of the health care jelly of Chinese herbs have nutritional value and can play the health care value of Chinese herbs.

3.4 Tea health care jelly
Currently used in the production of health jelly tea mainly oolong tea and green tea, as well as buckwheat tea. Oolong tea used in the preparation of health care jelly is mainly semi-fermented tea Tieguanyin, which contains polyphenolic compounds with strong antioxidant and biological activity, can remove free radicals in the body, but also instead of VC in the jelly for antioxidant preservatives.

Ma Tengfei et al. preparation of purple potato – konjac – oolong tea composite health jelly when added to Iron Goddess of Mercy developed a selenium-rich and anthocyanin-rich composite health jellies, which contains tea flavor and retains the antioxidant capacity of tea polyphenols.

Green tea contains a variety of vitamins, amino acids, proteins, lipids and minerals and other nutrients, has a thirst quenching, greasy refreshing, sterilization and anti-inflammatory, antihypertensive and vitality, dental protection and other health functions. Shan Yuan Kai and other pine needles and green tea as raw materials, adding sugar and compound gum modulation, the production of pine needles and green tea with a unique flavor and flavonoids and tea polyphenols nutrition, health care, smooth taste, color and lustre uniformity, moderately sweet and sour new nutritional health care jelly, pine needles and green tea deep processing provides a new way, the market has broad prospects.

Jia Juan and other preparations of lemon tea health care jelly tea extract, lemon and composite gum powder as the main raw material, with the lemon fragrance and the unique flavor of tea, rich in natural tea polyphenols and caffeine and other effective components of tea, both nutritional and health care efficacy of lemon tea health care jelly.

Tea extraction temperature, extraction time and the addition of extraction solution has a great impact on the color, aroma, taste and body of health jelly.

3.5 Health Jelly with Glutinous Rice Alcohol
At present, there is a class of health care jelly is wine health care jelly, such as sweet wine nutritional health care jelly, juniper sweet wine nutritional health care jelly, black bean sweet wine nutritional health care jelly, using sweet wine are glutinous rice sweet wine. Zong Liuxiang, etc. to Cortex Eucommia, eggs as raw materials and with auxiliary materials to develop a suitable for the middle-aged and elderly subhealthy people to eat Cortex Eucommia Sweet Wine Nutritional Health Jelly, which has high nutritional value, unique flavor, good organoleptic properties, without adding preservatives.

3.6 Other kinds of health care jelly
At present, there is also the use of pumpkin yogurt, kiwi/apple flavor vinegar jelly, spirulina, wheat seedlings and housefly larvae biological activity and its processing characteristics, the development of health jellies with rich nutrition and a variety of health functions.

Existing problems and development direction of health jellies

Problems and development direction

Most of the jelly products on the market at present belong to the traditional jelly with high sugar and acid, which is mainly made of gelatin, sweetener, flavor and color, etc. Some jellies are added with excessive synthetic color and preservative for the purpose of pursuing bright color and long shelf life, which is of low nutritive value and adversely affects the health of the consumers.

For this reason, the development of health care jelly can be considered from the following aspects:

(1) Research and development of sugar-free health jelly. For children who are in the period of growth and development, long-term consumption of sweets, the body metabolism produces a large number of metabolic wastes pyruvic acid, lactic acid, etc., resulting in children are prone to become acidic and lack of vitamins, thus affecting the development of the children’s brain and the maintenance of function.

For diabetics, it will undoubtedly increase the blood glucose concentration after consumption and aggravate the condition. Therefore, the development of sugar-free health jellies, or the use of sweeteners stevia, xylitol, etc. to replace sucrose and glucose, can effectively reduce the damage to the body of a large number of sugar metabolism.

(2) Solve the phenomenon of decolorization, browning, cracking, etc., to extend the shelf life. Most of the fruits in the jelly have different degrees of discoloration and browning phenomenon, especially the darker color of blueberries, strawberries, grapes and other varieties.

In order to solve the problem of discoloration and browning in health care jellies, firstly, the processing time should be shortened as much as possible, and cups and sealing films should be made of high barrier materials to reduce the permeability of the cups and sealing films, and to reduce the oxidative discoloration, browning or fission. Secondly, use natural coloring instead of synthetic coloring to make light-colored or colorless health jellies to avoid decolorization and browning problems.

(3) The quality of fruits and vegetables, gelling agent, sweetener and acidifier are the main factors affecting the quality of jelly. Preparation of health care jelly fruits, vegetables, tea, herbs, etc. can be used as raw materials for the preparation of the first raw materials should be broken into juice or made into pulp block and gelatin solution mixed well, and then according to the process of selecting sucrose, glucose, sweeteners, proteins, honey, strawberry juice, etc. Choose one of them as a sweetener, and sometimes need to add citric acid for color protection and acidity, and add potassium sorbate for antiseptic. Therefore, fruit pulp, fruit and vegetable juice, gelling agent, sweeteners and acidulants to add the amount and quality of the main factors affecting the quality of health jelly.

(4) The future mainstream trend of health jelly: high quality, natural, functional, healthy. China has a deep-rooted tradition of homology of food and medicine, food raw material resources are rich and diverse, the use of China’s traditional Chinese medicine theory guides the addition of fruit juice, pulp, fruit and vegetable juices, herbs, and even chocolate, innovative, high-end type of health care jelly continues to emerge, the texture of the tender supplemented by natural fruit and vegetable juices, and even glutinous rice wine, yogurt, tea, etc., the formation of a unique taste, light or colorless natural pigmentation health care jellies to meet the consumer’s demand for healthy, nutritious, taste multiple needs. It meets the multiple demands of consumers for health, nutrition and taste. Therefore, the future health jelly mainstream tends to high quality, natural, functional, healthy direction.