**6. References**

398 Food Industrial Processes – Methods and Equipment

analyzing indicated whether the product had enough heat treatment or not. To display temperature and time as a spread sheet on the left side of this figure, time interval of data was selected first at the bottom between in every 1, 2 or 5 minutes. Then the temperature and time only at this specific interval was shown in the spread sheet of GUI. Heat penetration and lethal rate profiles from all 4 probes were also displayed graphically. The x and y range of these 2 graphs were adjusted automatically according to process temperature and time span used. In addition, this visual basic form could be printed out for food safety

A computer program for on-line data acquisition and accomplished Fo assessment was developed by MS Visual Basic 6.0 language. This computer-based on-line device was able to evaluate the coldest point of the can in the retort and calculate process lethality or system Fo dynamically while sterilizing. Too much over or under process was avoidable for process design or schedule with the integration of such a device for on-line accomplished Fo determination during preprocessing. The setup of hardware and software for computerbased on-line assessment of sterilizing unit would be needed for the cases of new products,

Non-uniform heat distribution in retort always exists. The designed program was able to perform heat distribution evaluation by recording and displaying maximum/minimum temperature deviation at different locations in retort during holding temperature in sterilization process. Lower sterilization temperature at 110oC had lower temperature deviation (1.6-2.8%) in the retort during the holding temperature comparing to 4.1-11.6% at

121 oC. Thus lower temperature tended to lower the deviation.

documents.

Fig. 18. The result displayed by QuickCalFo

**4. Conclusion** 

processes or equipments.


**21** 

395

 *P.R.China* 

**Ice-Temperature Storage Technology** 

*Tianjin Key Lab of Refrigeration Technology, Tianjin University of Commerce,* 

The ice-temperature storage technology belongs to the no-freezing storage technology, in which the food is stored at a temperature from 0ºC to the freezing point. The fundamental thought of ice temperature storage technology is that the stored product is a living organism. After the cooling disposition on certain conditions, it can reach to an approximate "hibernate" state. Preserved at this state, the product can be maintained in good quality and its life can reach to the longest level since its metabolic rate is the smallest and so is the

The ice-temperature storage technology was originated from Japan. Their found that the freeze point of the snake, frog and meat is below 0°C for the antifreeze substance such as the sugar, the protein and alcohol and they can be kept as a living organism. The results pointed out that the temperature limit of life and death is below zero centigrade and at which temperature, the cell can be kept a living state. The effect of the ice-temperature storage

1. The ice-temperature storage can inhibit respiration, delay the respiratory peak and reduce the loss of nutrients. The exhaled volume of CO2 in the ice-temperature (-0.8°C)

2. The ice temperature storage won't destroy the cells, but improve the quality of fruits and vegetables in the vicinity of freezing temperature. In order to prevent from forming ice, fruits will secrete large amounts of antifreeze (its main ingredients are glucose, amino acids, aspartic acid etc.) to reduce the freezing point, or decompose the starch into sugar. These physiological changes improve the quality of fruits and vegetables in

3. The ice temperature can inhibit the growth of microbial efficiently. Under the condition of the ice temperature, water molecules in fruits or vegetables are arranged in an orderly state, which reduce the content of free water available for the microbial. In the short-period storage, the ice temperature can inhibit multiplication of microorganisms, better than the frozen temperature. In the long-term storage, the ice temperature and the frozen temperature maintain the same level of a reproduction rate of bacteria, fungi and low-temperature bacteria, which is much smaller than that of the cold temperature. 4. Since ice temperature can inhibit chemical reaction strongly, the food quality in ice temperature is better than that of the normal cold storage. The ice temperature also can

technology on the fresh food mainly includes the followings.

is less than that stored in normal temperature about 30% to 60%.

inhibit lipid oxidation, non-enzymatic and other chemical reaction.

**1. Introduction** 

energy consumption.

different degrees.

**of Fruits and Vegetables** 

Liu Bin, Cai Bihao and Shen Jiang

