A Review of Rice Authenticity/Adulteration Methods and Results

Abstract

Rice importance resides in its high consumption mainly in Asia and Africa and less in the EU. Several cultivars, both GM and non-GM, have established themselves in various regions depending mainly on the climatic and soil conditions. A high number of analytical, enzymic, and genomic analyses (instrumental) in conjunction with sensory analysis were applied (not always very successfully) towards detecting deliberate or non-deliberate rice adulteration. It was shown that the application of multivariate analysis to data obtained is very beneficial because it allows the effective discrimination of different origin, and/or cultivar rice. Although sensory analysis is based on a trained panel (subjective method), if this panel has been properly trained the adulteration results are comparable to those of the instrumental analysis obtained.

Keywords:

• Rice
• GM
• sensory analysis
• authentication
• Multivariate Analysis

Notes

^a g/100g of crude protein in Osborn fractions.

^b HEX: hexachloro-6-carboxyfluorescein; TET: tetrachloro-6-carboxyfluorescein; 6-FAM: 6-carboxyflourescein.

^c total mean values.

¹L/B: Length/Breadth ratio.

²Δ L/ Δ W: Ratio of difference in length of raw and cooked kernels to the difference in width of raw and cooked kernels.

* Chemical composition of rice bean seeds under uncooked (UC), 15 min pressure cooking (15 MPC) and 50 min boiling (50 MB) conditions (g per 100 g on dry weight basis)

^A in mol%.

^B in flour.

^C total in brown rice and milled rice grains with a degree of milling of 90% or 70% samples.

^D Total sugars expressed as weight percentage of each fraction(%) of ethanol-precipitated fractions of cereal polysaccharides aqueous-extracted at 25°C

^E yields as relative distribution of sugars.

^F WEPs: Water Extractable Polysaccharides, WUPs: Water Unextractable Polysaccharides (Native/Malt).

^A g/100 g of crude protein.

^B Rice beans.

^C Rice bran sample(s).

^D Buffer contained 0.1 M acetic acid, 3 M urea, and 0.01 M cetyltrimethylammonium bromide.

^E rice bran protein isolate (RBPI).

^A Rice bran sample(s).

^B Rice starch.

^C From the residue left after CM extraction (L: lipids, NL: neutral lipids, PL: phospholipids, and GL: glycolipids) (in mg/100 g in dry starch).

^D PEE-L: Petroleum ether extraction lipids, PWE-L: Aqueous propan-1-ol extraction lipids and Total: the sum of PEE-L and PWE-L, stored at 4°C for 4 months (in mg/g).

^A Rice bran sample(s).

^B Gallic acid eq.

^C Contents in fresh brown rice (ppm dry grain).

^D ppm of phenolic acids of white rice flour.

^E Wild rice hulls.

^a Methylarsonic acid (MMA) and dimethyarsinic acid (DMA).

^b certified rice sample.

^d Mean value from the Determination of Trace Cadmium in Rice Samples.

^e in digest or 0.002 ppm in solid samples.

^f from water samples simultaneously examined.

^g Polished rice samples—Diethyldithiocarbamate (DDTC) into 4-methylpentan-Z-one (MIBK).

^h rice bran sample(s).

ⁱ ALC: alizarine complexone; DME: dropping mercury electrode.

^j brown/white rice sample.

^a CTAB^:SDS: SAAS: SAAS-SCIQ-CBSR kit, Shanghai Academy of Agricultural Science, Shanghai,China.

^b Dellaporta et al., 1983.