MIDINFRARED AS A NEW TOOL FOR DETECTING ADULTERATION IN FRUIT PRODUCTS

This paper illustrates the use of attenuated total reflectance (ATR) s pectra of fruit purees or jams, and diffuse reflectance (DRIFT) spectr a of jams, to provide the chemical information necessary to check the composition and authenticity of these products. The fingerprint region contains information reflecting the carbohydrate, acid, and pectin co ntent. Although differences between products from different fruit type s, or between genuine and adulterated samples, can be seen in the spec tra by eye, the samples cannot be identified unambiguously by visual i nspection. Statistical methods can aid this identification, however. A n example of the use of principal component analysis is presented, ena bling genuine raspberry purees to be distinguished from raspberry pure es doctored by the addition of sucrose solution to a level of about 6% sucrose.