Page 38 - O Bunge Oils Resource Guide

major Factors Affecting Shortening Breakdown
• WATER
• POLYMERIZATION
• OXYGEN
• TURNOVER / TIME
• EXTRACTABLES
• HEAT (Fry Temperature) • CONTAMINATION
water Reaction or hydrolysis
This is the reaction of the shortening with moisture wherein the triglyceride or fat molecule is broken down . Technically this change is expressed as the percentage of free fatty acids . As more molecules are broken up, free fatty acids begin to make the shortening objectionable . It will begin to smoke and darken .
Excessive water is unacceptable for several reasons:
1. Waterreactswithshorteningtocausefaster break-down . This will be evidenced by smoking and a dark unacceptable shortening color .
2. Watercauseskettletemperaturestodropwhich means a longer frying time than is desired, the potential for undercooked food, and a need for more energy to bring the temperature back up to an acceptable frying range .
3. Spatteringcanoccuraroundthefryingarea creating a dangerous safety hazard .
Oxidation
During the frying operation, the surface of the shortening is protected by a blanket of steam rising from the foods being fried . During slack periods, air comes in contact with the surface of the shortening . The oxygen in the air reacts with the shortening and speeds up its deterioration . Vigorous pouring from container to container when filling the fryer or filtering, for example, can also over- expose your short- ening to oxygen .
hYDROLYSiS – Practically speaking, you should combat water introduc- tion by draining or blotting foods before placing them in the fryer, particularly if the foods are frozen and have a buildup of ice crystals on them . Dry fryer completely after the boiling out process .
OxiDATiON – Oxygen in the air reacts with shortening and speeds up deterioration . Reducing kettle tem- peratures to 150°F from 200°F when the shortening is not being used will reduce the rate of oxidation, allowing for longer frylife .
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