Based on SNI 01-4493-1998, the quality of sweet potato can be classified into 3 (three) quality classes which are quality I, II and III. The quality requirements of sweet potato is divided into two general conditions: sweet potatoes should not have foreign odors, sweet potatoes must be free of pests and diseases, yams must be free of chemicals such as insecticides and fungicides, sweet potatoes should have a uniform color, shape and size tubers, yams should have reached optimal physiological maturity and sweet potatoes should be in a clean condition.
Sweet Potato Quality Testing Methods
Based on SNI 01-4493-1998 sweet potato quality testing methods for quality parameters related to the general quality requirements (foreign odors, pests and diseases, uniformity of color, shape and size of the tuber, the level of physiological maturity and the number of tuber defects), is testing the organoleptic which uses the senses of sight, smell, and touch by a trained examiner. As for the quality parameters water content, fiber content and the starch content, the testing method used is a method of oven (AOAC 1984) in SNI 01-4493-1998, acid method, and the method Anthrone SNI 01-4493-1998, SNI 01-4493- 1998.
In testing the quality of commodity tubers, of course, we only test a representative sample of the commodity tubers to be tested. Sampling method to be tested between one type of testing by other testing different, it depends on the type of sample (solid, paste or liquid) and also the type of analysis, eg for microbiological analysis in contrast to chemical analysis.
a) How Sampling
Sampling method for testing commodities according to SNI 01-4493-1998 sweet potatoes are as follows:
(1) The packaging chosen randomly determined as the square root of the number of packs in a lot, and then from each package taken as much as 10 seed tubers which covers the upper, middle, and bottom.
(2) The sample is taken without causing damage.
(3) Sample obtained randomly divided in two and carried out several times to obtain an analysis sample of 50 seeds.
b) The principle of the test
Sweet potato quality testing grouped by test qualitative and quantitative test. In the qualitative test tested organoleptic using the senses of sight, smell, and touch by a trained examiner. The way the examination is an example of the analysis of as many as 50 pieces are all checked, in accordance with the desired criteria. The trick tubers quartered longitudinally, and then examined according to the criteria of each. Physical analysis was conducted in the laboratory.
While the quantitative test test principle is as follows:
(1) Measurement of weight of tubers of sweet potato is done by weighing the scales appropriate to use the tool.
(2) Examination conducted organoleptic defect bulbs good appearance from the outside and on the inside.
(3) Measurement of water content in thermogravimetri, while the fiber content measurements by separating the non-fiber raw materials by dissolving acid and a strong base in hot conditions.
(4) Measurement of the content of starch separation nonpati material by dissolving the acid and a strong base in the centrifuge.