sensitivity and specifity of spectrophotometer and polarimeter methodes in the detection of fraud of produced lemon juice in Iran

Daily use and persistence in food consumption, provides grounds for fraudsters to reduce production costs act to various adulterations and thereby threat people's health. This study carried out to survey new distinguish methods in the detection of fraud of produced lemon juice in Iran. Study was conducted with a diagnostic design on 45 samples of lemon juice from 45 factories of producing lemon juice in Iran. The tests of the amount of sodium, potassium, optical rotation, total amino acid and polyphenols were done according to reference books for the detection of fraud in produced lemon juice.Furthermore, the tests of amount of brix, pH, acidity and formalin index were conducted according to national standard of Iran. The condition of produced lemon juice of Iran showed that there was a significant difference between mean sodium of normal versus feigned lemon juice [23.73 vs. 87.33 mg/dL, P<0.0001], potassium [149.07 vs. 63.56 mg/dL, P<0.0001], optical rotation [1.91 vs. 0.72 meq/dL, P<0.0001], total amino acid [247.79 vs. 84.66 mg/dL, P<0.0001] and polyphenols [1.8 vs. 0.81, P<0.0001]. Sensitivity of total amino acid, polyphenols, optical rotation, sodium, potassium, brix, acidity, formalin index, matter dry and pH methods compared with protein were 91.3, 100, 100,100,100, 66.17, 66.17, 66.17, 66.17 and 68.96, respectively. Values of potassium, optical rotation, total amino acid and polyphenols in feigned samples were low but value of sodium was high