Analysis of respiration of the hottest fruits and

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Analysis of respiration of fruits and vegetables (II)

3. Respiratory heat

respiratory heat is the part of heat generated in the process of respiration and emitted into the environment in addition to life sustaining activities, which is usually expressed in B.t.u. (British thermal unit). Because the method of measuring respiratory heat is extremely complex, when fruits and vegetables are stored and transported, the method of measuring respiratory rate is often used to indirectly calculate their respiratory heat at a general working temperature

when a large number of products are piled up after harvest or lack of ventilation and heat dissipation devices during long-distance transportation, the temperature of the product itself rises because the respiratory heat cannot be dissipated, which in turn stimulates breathing, releases more respiratory heat, and accelerates the deterioration of the product. Therefore, the heat of respiration should be eliminated as soon as possible during storage to reduce the product temperature; However, in the cold season in the north, when the ambient temperature is lower than the temperature required by the product, the product uses the respiratory heat released by itself to keep warm, so as to prevent cold, and ensure that the gap is 0.05 0.08 mm and the occurrence of freezing injury

4. Respiratory temperature coefficient

within the physiological temperature range, the ratio of respiratory rate when the temperature rises by 10 ℃ to the respiratory rate at the original temperature is the temperature coefficient, which is expressed by Q10; It can reflect the change degree of respiratory rate with temperature. For example, when q10=2---2.5, it means that the respiratory rate has increased by 1---1.5 times. The higher the value, the greater the impact of temperature on product respiration. The research shows that the Q10 of fruits and vegetables is large at low temperature. Therefore, the temperature should be strictly controlled during storage, that is, maintaining a suitable and stable low temperature is the premise of good storage

5. Respiratory peak

in the process of fruit development, respiratory intensity varies with different stages of development (Fig. 1?/font 4)

the respiratory intensity was high when the fruit was young, and then decreased with the process of fruit ripening. When the fruit enters the ripening stage, the respiratory intensity of some fruits and vegetables suddenly increases, reaching the peak (called the respiratory peak), and then the respiration decreases. The fruit of Jinan new era experimental machine after-sales professional aging and death, with the emergence of the respiratory peak, the metabolism in the body changes greatly. This kind of fruits and vegetables is called climacteric or respiratory peak fruits and vegetables, which is called respiratory climacteric. The respiratory intensity of another kind of fruits and vegetables does not increase when they enter the full ripening stage, and has always maintained a low level of respiratory curve of climacteric and non climacteric fruits. The respiratory intensity has been reduced after harvest until aging and death. This kind of fruits and vegetables is called non climacteric fruits. Table 1-4 summarizes two types of respiration of fruits. The table shows that there is no obvious correlation between respiration types and plant classification or fruit tissue structure

table respiration type of fruits and vegetables after harvest (kader, 1992)

(to be continued)

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