Physical preservation measures of the hottest trop

Physical preservation measures for tropical fruits (Part 1)

there are three kinds of post harvest preservation measures for tropical fruits: physical measures, chemical measures and biological measures. They have different effects and different emphases; For a specific fruit, several measures are often used separately or at the same time

physical protection measures

1 Placed in the dark

sunlight and artificial light will accelerate the deterioration of fruits, so they should be stored in the dark

2. The effect of low temperature

is obvious at about 0 ℃ or above, but some tropical fruits with the best storage temperature of 5 ℃ to 12 ℃ may cause adverse consequences (Table 3)

Table 3 the average storage of several tropical fruits wishes the meeting to be better and better! Optimal temperature (T) and relative humidity (HR)

fruit t (℃) HR (%) period

citrus months

pineapple 890 weeks

avocado 790 weeks

banana 1290 days

mango 890 weeks

papaya 4 weeks

① for fruits in bulk or small-size packaging, they can be cooled by air conditioners continuously or intermittently

② put the fruit in cold water or ice water for a few minutes, and the cooling effect is more obvious. Ball screw has the highest accuracy Nu v

there are many ways to quickly reduce the internal temperature of fruits

③ placing fruits in vacuum freezers has the most obvious cooling effect, which is especially suitable for fruits harvested in the field

according to the shape, size and temperature demand of fruits, people choose the best cooling method and temperature according to local conditions. For example, bananas and pineapples are suitable for cooling with cold water, while oranges cannot be cooled with vacuum freezing. These cooling technologies are very suitable for a beautiful quality battle on the freezing and packaging assembly line. This assembly line is best located in the fruit producing area for timely processing after picking

3. Ventilation

reasonable ventilation will not cause fruit drying. Air circulation is very important. Wind can reduce unnecessary volatile substances (ethylene, CO2, some flavors) produced by fruits. It is unnecessary to blow continuously. The blowing cycle depends on the different characteristics of fruits and the required temperature. In general, the volume of fresh air blown in is about times of the indoor volume. The harmful substances volatilized from fruits are reduced by differentiation equipment (activated carbon sieve, ozone machine, tungsten lamp can reduce the concentration of vinyl olefins)

4. Humidity

according to the storage time and temperature of the fruit, people choose the best relative humidity, which should be strictly observed, because too low humidity (50%hr) will cause the fruit to lose water, lose weight and dry, and too high humidity and saturation will accelerate the fruit to mildew

(to be continued)