CN1094041C

CN1094041C - Process for ordinary-temp antistaling of longan

Info

Publication number: CN1094041C
Application number: CN00117509A
Authority: CN
Inventors: 吴振先; 陈维信; 苏美霞; 季作梁
Original assignee: South China Agricultural University
Current assignee: South China Agricultural University
Priority date: 2000-10-18
Filing date: 2000-10-18
Publication date: 2002-11-13
Anticipated expiration: 2020-10-18
Also published as: CN1289544A

Abstract

The present invention relates to longan refreshing technology. Longan fruits harvested of eight or nine ripened are selected and classified, and then, soaked by a refreshing agent for 1 to 2 minutes; the longan fruits are aired; a polyethylene bag with 5 % of perforation is used as an inner package, and a plastic frame or a paper box with ventilating holes is used as an outer package; the longan fruits are stored and transported at normal temperature. The present invention can effectively prolong longan storage and transport period at normal temperature. The used film preparation is a food additive which is harmless to human bodies. The decay loss of longan in the process of storage and transport is obviously reduced by refreshment processing.

Description

The longan normal temperature fresh-keeping method

The present invention relates to the fruit freshness preserving technology, especially the extending longan shelf life technology.

Longan is one of China's south special product fruit, has very high nutritive value and economic worth.But because longan is gathered in high temperature season, the longan fruit metabolism is very vigorous, is easy to rotten rotting after adopting, and loses its commodity value.Annual owing to adopt post processing and storage is improper, it is very serious to cause longan to adopt the back loss.

The low temperature storing and transporting facility is all adopted in Long-term Storage of longan and long-distance transport both at home and abroad, except the cold chain circulation, adds the use sulfur dioxide treatment abroad, can carry out storage and the transportation of long period, but have problems such as sulphur is residual, pulp reddens.And domestic employing low temperature adds the fresh-keeping method of medicine repairing, and freshness date is shorter, and endocarp begins browning after more than ten day, and pulp begins self-dissolving.

To the research of longan room temperature storage preservation technique, both at home and abroad also seldom, because the metabolism of longan is very vigorous, the utmost point be cannot say for sure aquatic foods at normal temperatures.But the facility of the refrigeration ability that China is present and low temperature circulation also lacks very much, and the seasonality of YEAST IN LONGAN PRODUCTION and regionality are very strong, and present cold chain circulation situation is difficult to satisfy produce to go up needs that timely longan with maturation be transported to pin ground in short-term in.

The objective of the invention is the characteristics according to longan fruit, promptly pericarp structure is loose, and the base of fruit position begins self-dissolving at first, fruit adopts that metabolism is vigorous under the normal temperature of back, dehydration is fast and characteristics such as easy aging, utilize antistaling agent for longan to handle, come the delayed fruit aging, the self-dissolving speed of the pulp that slows down, suppress the physiological metabolism of fruit, slow down the dehydrating speed of fruit, suppress harmful microorganism, reach the maintenance fruit quality, reduce and rot, prolong the purpose that stores and transports the phase at normal temperatures.

The present invention be with the longan after gathering through selecting, used the antistaling agent for longan immersion treatment then 1～2 minute, taking-up is dried, and is that 5% Polythene Bag is an inner packing with perforation field, is external packing with the carton of frame of plastic or tool air vent.Under normal temperature condition, store and transport, prolong the storing phase of longan effectively.

The present invention has following characteristics: (1) can prolong the longan storing phase effectively under normal temperature condition, can store and transport 7～9 days under 20 ℃～25 ℃.(2) according to the characteristics of longan fruit, select suitable antistaling agent for use, fresh-keeping effect is obvious.Used antistaling agent is food additives, and is harmless.(3) obviously reduced rotten loss in the longan fruit storage.

The present invention is achieved in that

(1) gather: harvest maturity is a key factor that concerns longan postharvest storage effect and quality thereof.The longan maturity of optimum storage is eighty per cant to ninety percent, and gloss appears in the blackening fully of seed this moment, and fruit has elasticity.Maturity is low excessively, and fruit is zoon not as yet, and organic substances such as sugar are accumulated fully, and metabolism is vigorous, so storability and quality are all relatively poor.Maturity is too high, can cause the fruit hardening on the one hand, can occur moving back sugared phenomenon on the other hand, and this fruit also is difficult to Long-term Storage, and the outward appearance and the local flavor of fruit is also relatively poor after handling.Gather and should carry out when dew has just been done in the morning of fine day, not under burning sun or the rainy day gather.Longan should whole bunch be gathered.

(2) select classification: unsound fruits such as sick wormed fruit, no base of a fruit fruit, brown stain fruit, dehiscent fruit, malformed fruit are easy to cause rotten in storage or transportation; Reject the fruit that rots.In addition, according to requirement of client, longan can be pressed fruit size, bunch classifications such as weight.The longan of select loosely is deposited in frame of plastic or the bamboo square-bottomed bamboo basket, does not compress.

(3) whole bunch of longan of select is immersed in the antistaling agent 1～2 minute, comprises that branch all will steep in the antistaling agent.

(4) dry: the longan fruit after antistaling agent is handled, just can pack after must drying.Can utilize air-conditioned room or fan to accelerate the speed of drying.

(5) packing: longan is dried the back according to common packaging process, and the base of a fruit fruit that rejects once more, dehiscent fruit grade fruit have the longan proper alignment in the frame of plastic of polythene film bag of 5% perforation field at liner.

(6) transportation: packaged longan can utilize the normal temperature car to transport, and Che Shangying has hood, prevents to expose to the sun and rain, in transit should be with the paulin that keeps off the rain of railway carriage front portion, allow air current flow in the compartment, and be beneficial to and remove fruits respiratory heat.

(7) sell: should in time sell after transporting to market.Otherwise at high temperature the flavor quality of fruit descends very fast.

The present invention is applicable to transportation and the storage of 10 days left and right sides longans.If temperature is higher than 25 ℃, the storage haulage time can slightly shorten, but room temperature storage can adopt air-conditioning to carry out a little cooling, helps to prolong its storage period.

(1). antistaling agent 1 prescription: contain the 1g shitosan in the 1kg antistaling agent, 45% Te Keduo 2.2ml or 25% executes and protects gram 1ml.

Compound method: because shitosan can not directly be dissolved in water, the acetum of Ying Xianyong a small amount of 36% or the citric acid solution of 0.1g/ml be dissolving earlier, adds water to 1kg again, adds 45% Te Keduo 2.2ml or 25% then and executes guarantor's gram 1ml, mix, get antistaling agent 1.100 kilograms of fresh-keeping liquids can be handled 2～3 tons of longan fruits.

After longan selects, after 1～2 minute, dry (not handle in contrast) with a little solution immersions, packing is preserved down at 20～25 ℃, and after 5 days, the contrast fruit has begun mildew, and the pericarp browning still keeps the original color of pericarp, no mildew and handle fruit.Preserved 7 days, contrast has 10% fruit rot approximately, handles fruit and remains unchanged substantially.Preserved 9 days, the contrast fruit has 25% fruit rot, and the whole brownings of pericarp only have 3% fruit rot and handle fruit, and fruit colour is deepening slightly.Preserved 11 days, contrast fruit rotting rate reaches 54%, has only 12% fruit rot and handle fruit.

(2). antistaling agent 2 prescriptions: contain the 5g carboxymethyl cellulose in the 1kg antistaling agent, 45% Te Keduo 2.2ml or 25% executes and protects gram 1ml.

Compound method: with low amounts of water dissolving 5g carboxymethyl cellulose, add water to 1kg more earlier, leave standstill a period of time (about 2 hours), treat whole solution clarification, add 45% Te Keduo 22ml or 25% again and execute guarantor's gram 1ml, mix.100 kilograms of fresh-keeping liquids can be handled 2～3 tons of longan fruits.

After longan selects, after 1～2 minute, dry (not handle in contrast) with a little solution immersions, packing is preserved down at 20～25 ℃, and after 5 days, the contrast fruit has begun mildew, and the pericarp browning still keeps the original color of pericarp, no mildew and handle fruit.Preserved 7 days, contrast has 10% fruit rot approximately, handles fruit and remains unchanged substantially.Preserved 9 days, the contrast fruit has 25% fruit rot, and the whole brownings of pericarp only have 3% fruit rot and handle fruit, and fruit colour is deepening slightly.Preserved 11 days, contrast fruit rotting rate reaches 54%, has only 10% fruit rot and handle fruit.

Claims

1. longan normal temperature fresh-keeping method, it is characterized in that the selective maturation degree is eighty per cant to ninety percent, gather fine morning, through roguing select excellent after the cluster longan, put into antistaling agent (1) solution, or in antistaling agent (2) solution, soaked 1～2 minute, dry, be loaded on liner have 5% perforation field Polythene Bag frame of plastic or have in the carton of air vent, in down storing of normal temperature;

Antistaling agent (1) prescription: contain the 1g shitosan in the 1kg antistaling agent, 45% Te Keduo 2.2ml or 25% executes and protects gram 1ml;

Antistaling agent (2) prescription: contain the 5g carboxymethyl cellulose in the 1kg antistaling agent, 45% Te Keduo 2.2ml or 25% executes and protects gram 1ml.