VEGETABLE AND FRUIT DEHYDRATION 143 



devote as much time as possible to the work of the laboratory without 

 too many additional duties. 



Equipment is important. The laboratory should have well-lighted, 

 roomy space, shut off from noises and odors. It should be free of 

 dust, steam, and excessive vibration. Some of the necessary facili- 

 ties and important items of equipment are work benches or tables, 

 water, gas, electricity, and a sink. Although not essential, a refrig- 

 erator is very useful. Cupboard space for equipment, glassware, 

 and supplies, and shelves for sample storage should be provided. 

 Other items will be mentioned in subsequent discussions of the various 

 types of tests and inspection work that are ordinarily carried on in 

 plant-control laboratories. 



Analysis, however carefully made, can do no more than give the 

 composition of the sample. It is essential therefore that the sample 

 be taken in such a manner that it will represent the lot under test. 

 It must be remembered that variations in composition can be found in 

 almost any lot of material. Portions of the material must be taken 

 from various parts of the lot under test, carefully mixed, and either 

 quartered by hand or, if the material is suitable, portioned with a 

 riffle sampler. In this way a representative sample can be obtained. 

 The remainer of the collected material can be returned to the lot. 



After the sample has been collected it should be treated in such 

 a manner that it will have the same composition when analyzed as 

 when collected. Refrigeration can be used to hold samples for short 

 periods of time. Samples to be analyzed for moisture must be kept 

 tightly sealed until the analysis is made. Prompt analysis of samples 

 after collection is always desirable and is almost a necessity when the 

 sample is fresh material. 



Examination of Raw Product 



Since the quality of processed foods is greatly influenced by the 

 stage of maturity of the commodity when harvested, canners and 

 freezers give special attention to the maturity of raw products, and 

 no less attention is required in dehydration. Other factors, such as 

 color, uniformity, insect infestation, dirtiness, mechanical damage, 

 and wilted condition are important and some attention has been di- 

 rected toward the development of objective tests for evaluating some 

 of these factors. Materials which would be rejected for canning or 

 freezing are equally unacceptable for dehydration. Unfortunately 

 few satisfactory tests for quality of the raw product have been devised 

 and reliance must be based largely on general appearance as interpreted 

 by an experienced operator. A few commonly employed tests are 

 briefly described below. 



TENDEROMETER TEST (PEAS) 



One of the most recently developed methods for peas measures the 

 force required to press a definite volume through a standard grid ; the 

 force necessary to shear the peas is directly proportional to toughness 

 and inversely proportional to tenderness. The instrument used for 

 this purpose is known as the tenderometer. 



Procedure : The tenderometer value is determined for each load of shelled peas 

 as it comes to the packing plant. Care must be taken to obtain a representative 

 sample of the load. This is usually accomplished by filling a No. 10 can from lug 

 boxes at several points. The peas are then cleaned and thoroughly mixed. 



