Dissertation
Dissertation > Industrial Technology > Light industry,handicrafts > Food Industry > Fruits, vegetables,nuts processing industry > Fruit and processed foods

Permeating Calcium Fresh-Keeping Technologies and Production Quality Control of Deepfreeze Strawberry

Author TangHao
Tutor GuZhenXin
School Nanjing Agricultural College
Course Food Engineering
Keywords strawberry permeating calcium quick-frozen HACCP quality control
CLC TS255.4
Type Master's thesis
Year 2009
Downloads 22
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Strawberry (Fragaria ananassa Duch) is a perennial herbaceous plant which belongs to Rosaceae, Fragaria. The strawberry is brightly-colored, soft and juicy, with a high nutritional value, and its production ranks first in the small berries fields, is a kind of fruit with relatively high economic value. But the loss is very significant in the storage and transportation as strawberry fruit is very delicate, fresh-keeping time is short.frozen strawberries can achieve long-term storage purposes.Frozen strawberries tend to look soft rotten and fruit-shaped blur after been thawed, which greatly reducing the product value of the goods. A strawberry variety, "feng xiang" was taken as experimental material, sprayed with 0.5%-1.5% calcium chloride solution during storage. The storage quality indices such as respiration, firmness, weight loss, rot index, organic acid and relative electric conductance(Rec.) of strawberry were investigated.The results indicated that calcium chloride treatment could decrease respiration and rot indexes, but Rec. And organic acid changed very little. Frozen strawberry which has been treated with calcium chloride can maintain a good appearance of products, and enhance product value.Therefore, it is important significance to establish the Hazard analysis critical control point (HACCP) of strawberry production to improve its product quality.In this paper, the application of HACCP in quick-frozen strawberry was studied. After establishing the HACCP system for quick-frozen strawberry product, tracing research was made to evaluate the validity of this system to control critical hazard. The main hazards in quick-frozen strawberry production were residue of pesticide, microorganism and Metal Residual. The critical control points were identified as acceptance of raw materials, ozone immersion and detection of residual metal. Aiming at the 3 critical control points above, particular critical limits were made and corresponding targets were formed. The food and raw materials should be obtained from non-polluted vegetables production areas. Ozone immersion should be completed in 0.075 mg/L for 3 min. The particular critical limits of residual metal were Fe≤ψ1.5 mm, SuS≤ψ2.5 mm.Attempts had been made to compare the safety of products before and after the implementation of HACCP system. The results showed that the production base of strawberry accord with the requirements of non-polluted vegetables production areas. After ozone immersion, food borne microorganisms were lower and the products were more eligible after the implementation of HACCP system. The residual metal reached national standard. These suggested that HACCP was a good method to improve the safety of the quick-frozen strawberry.

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