Quality change and control during the storage of Fresh-cut pear
Pear, one of high yield fruits, is well-known for its nutrition and health value, as well as its abundance in varities. Minimization for process on pear is a significant method which could extend shelf life, bringing more value added and increasing the integrated output value. The pear would become browning,soft,sensitive to micro organism, and bring out nutrition loss, because of the harmness caused by machine, leading to quality issue and reducing of storage life,the quality and commercialization of pear products. In this acticle, it will make research for the appearance,hardness and nutrition qualities in different varieties, the use of ascorbic acid, Calcium ascorbate and citric acid treatment on the quality of pear during storage, based the large comsuming fruit. The main conclusions and results were as followings:
1.The changes of quality of different fresh-cut pears: these varieties of fresh-cut pears has similar variation of color, crispness, hardness and the content of reducing sugar, but the content of vitamin C is different from each other and is decreasing all the time, the content of vitamin C in Huangguan Pear is higher, followed by Suisho. Different varieties may have various content of soluble phenolic. The activities of PPO were quite different and had big changes during the storage period.
Suisho is suitable for fresh-cut processing, because of slight browning,better hardness and crispness,less nutrition loss, and woret cellular membrane pemeablity. For six days, it could keep good qualities. Followed by Whangkeumbae, whose PPO activity is low, brown degree is low, and hardness is appropriate. Sydney, Changba pear, Laiyang pear is not suitable for processing, because of high brown degress and soft tissue.
2.The treatment of ascorbic acid has a good impact on quality of pear, which could alleviate brown degree, decrease the activity of PPO, lower the consuming of phenolic and reducing sugar, as well as increasing the content of vitamin C, which is a source of vitamin supplement, and there is no significant effect on crispness and hardness.
3. The treatment of Calcium ascorbate could alleviate brown degree, decrease cellular membrane permeability, the activity of PPO and the consuming of Vitamin C, and it is beneficial to maintain level of crispness and hardness, which could keep good superficial quality and trophic value.
4.The treatment of citric acid could alleviate brown degree, decrease the consuming of soluble phenolic, slow down the activity of PPO, and harden pear tissue at some level,but this treatment could not decrease the cousuming of vitamin C and reducing sugar significantly.
5.The results of composite inhibitors orthogonal test were as below: different browning inhibitors have various effects when applied, ascorbic acid have marked is impact on color and luster degrees, followed by citric acid and Calcium ascorbate. Calcium ascorbate is more suitbable than ascorbic acid and citric acid when applied to keep crispness. With regarding to hardness, Calcium ascorbate is preferable than citric acid and ascorbic acid. Taking all three parameters into consideration,best proportioning is obtained that Calcium ascorbate is 4.0g/100g,ascorbic acid is 2.4g/100g,and citric acid is 1.0g/100g.