12 Lecture 3 Nov 2015 Modified and Controlled Atmosphere APP

12 Lecture 3 Nov 2015 Modified and Controlled Atmosphere...

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11/3/2015 1 4010 Food Processing II Modified and Controlled atmosphere storage and packaging of food November 3, 2015 1 (Adapted from D. Daugelaite, Food Science, UofM, 2014) Introduction In 1930s and 1940s fresh apples and pear were placed in enclosed warehouses The natural respiration of the fruit reduced the oxygen and increased the carbon dioxide within the warehouse sufficiently to significantly slow respiration Apples could be consumed as long as six months after the original harvest (about double the normal cold storage shelf life) 2 Introduction 3 Air composition is essentially O 2 and N 2 20.96% O 2 <0.1% He <0.9% Ar 78.08% N 2 <CO 2 <0.01% H 2 Modification of air composition is a main basis for Controlled atmosphere (CA) and modified atmosphere (MA) storage and packaging MA and CA difference The CA and MA imply using an atmospheric compositions that is different from air, but they differ in the degree of their control of the gases concentrations. The main feature distinguishing MA from controlled atmosphere (CA) is that , in the case of MA, active human involvement stops at the moment of sealing. 4 MA and CA difference Modified atmosphere (MA) is a form of packaging involving the removal of air from the pack and its replacement with a mixture of gases. MA is used when the control of the storage atmosphere is not closely controlled, such as in plastic film packaging. Control atmosphere (CA) generally refers to decreased O 2 and increased CO 2 concentrations, by a precise control of the gas composition. CA requires precise control of O 2 and CO 2 concentration around fresh produce and involves large specialised storage buildings and sophisticated operation equipment. Used for long-term storage 5 O 2 : - preserve the red color of meat - avoid deterioration by anaerobic microorganism CO 2 : - avoid the development of molds and bacteria N 2 : - avoid rancidity - avoid deterioration caused by molds 6 The gases used in MAP/CAP
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11/3/2015 2 When O 2 CO 2 Respiration is slower Growth of microorganism is inhibited Fruit ripening is slow down Lower the risk of chilling injury Condition: the temperature of storage the lower the better 7 The gases used in MAP/CAP Goals of MA and CA Reduction of metabolic processes, especially respiration Delay ripening (removing ethylene due to cell respiration)
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