a) Method of sampling and sample preparation
Sampling method in accordance with ISO 0428, manual sampling solids. While the sample preparation for testing the quality of tapioca according to SNI 01-3451-2011 consists of sample preparation for microbiological tests, organoleptic and chemical analysis. Sampling for microbiological testing performed first, followed by sampling for organoleptic and chemical tests.
Sample preparation for microbiological test: Unpack example tapioca and aseptically grab samples of 400 g and place in a sterile sample bottle. Preparation examples for organoleptic test: Unpack example tapioca and grab samples to taste and place in a sample bottle clean and dry. Sample preparation for chemical analysis: Unpack tapioca and grab samples of 400 g and then placed in sample bottles are clean and dry.
b) The principle of the test
Perinsip tapioca quality testing for the state test parameters (shape, smell, color) is the observation of the sample with the five senses conducted by panelists who have competence organoleptic testing. The principle of quality Pengujan tapioca quantitatively according to SNI 01-3451-2011 are as follows:
(1) The moisture content is calculated based on weight lost during heating in an oven at temperature (130 ± 3) ° C.
(2) The ash content is calculated based on the weight of the ash formed during the combustion in the furnace at a temperature of (550 + 5) ° C until a white ash.
(3) levels of crude fiber is the part that can not be hydrolyzed by sulfuric acid (H2SO4 1.25%) and sodium hydroxide (NaOH 3.25%). Sections were calculated gravimetrically.
(4) The starch content is hydrolysis of carbohydrates into monosaccharides that can reduce Cu2 + to Cu +. Excess Cu 2+ can be iodometri dititar.
(5) The degree of white is light reflection measurement standard sample with MgO
(6) The degree of dissolution of the acid are organic acids in a sample by using certain organic solvents (alcohol 95%) followed by penitaran with alkali (NaOH).
(7) Metal Contamination of Cadmium (Cd) and lead (Pb), namely destruction example by dry ashing at a temperature of 450 ° C followed by dissolution in acid solution. Dissolved metal calculated using the tool Atomic Absorption Spectrophotometer (AAS) with a maximum wavelength of 228.8 nm to 283.3 nm for Cd and Pb.
(8) Contamination metal tin (Sn) is an example didekstruksi with HNO3 and HCl then add KCl to reduce interference. Sn read using Atomic Absorption Spectrophotometer (AAS) at a wavelength of 235.5 nm with a maximum of N2O-C2H2 flame oxidation.
(9) of metal contaminants Mercury (Hg) is a reaction between mercury compounds with NaBH4 or SnCl2 under acidic conditions to form the atomic gas Hg. The amount of Hg formed Hg proportional to the absorbance is read using Atomic Absorption Spectrophotometer (AAS) without flame at a wavelength of 253.7 nm maximum.
(10) Microbial Contamination: The figure of total plate that is aerobic mesophyll bacteria growth after the sample was incubated in the appropriate seeding for 48 hours at a temperature (35 ± 1) ° C.
(11) Microbial Contamination: Escherichia coli is Escherichia coli growth is characterized by the formation of gas in the Durham tube, followed by biochemical tests and further referenced in Table APM (Figures Most Likely).