Volatile Organic Compounds, Evaluation Methods and Processing Properties for Cooked Rice Flavor

Abstract

Rice (Oryza sativa L.), as the main refined grain in China, has attracted much attention in terms of quality. Rice is usually consumed after cooking, and it is a commonly staple food. Nowdays, people's requirements for cooked rice focus more on the taste characteristics and quality. Furthermore, aroma is one of the primary sensory reference points, which is the most intuitive way for people to judge cooked rice. By integrating and analyzing the researches of cooked rice aroma identification in recent five years, this paper expounds the extraction and identification methods (sensory evaluation method, GC-MS, SPME, MOS sensors, electronic nose, etc.) of the flavor substances in cooked rice, as the processing methods and properties of cooked rice, and the volatile organic compounds of cooked rice under different conditions are summarized as well. Graphical abstract

Dynamic Changes in Volatiles, Soluble Sugars, and Fatty Acids in Glutinous Rice during Cooking

“…Washing raw rice with water is often carried out before cooking to remove hull and other dust, and is thought to be an effective process to ameliorate the aroma of cooked rice [ 8 ]. After being washed, the total volatiles of rice decreased to (33.03 ± 0.85) × 10 6 and (33.19 ± 3.37) × 10 6 for Chunjiangnuo and Fuxiangnuo, respectively.…”

“…Rice is usually consumed in the form of cooked rice, processed after hydrothermal cooking. The processing technology affects the quality of the final aroma of cooked rice [ 8 ]. During cooking, the aroma formation of cooked rice is closely related to complex chemical reactions, including the Maillard reaction, lipid oxidation, and thermal degradation reactions, etc.…”

“…The post-cooking stage includes treatments such as retorting, canning, cooling, freezing, drying, and storage of cooked rice [ 9 ]. Different processes not only affect the texture and nutritional value of final cooked rice [ 10 , 11 ] but also greatly impact the volatile profile [ 8 , 9 ].…”

“…The water-to-rice ratio significantly affected rice texture but had little effect on flavor [ 17 ]. Cooking pressure had significant effects on the flavor of cooked rice [ 8 ]. High-pressure cooking significantly decreased off-flavor compounds compared to low-pressure cooking [ 18 ].…”

Metabolomics approach to identify key volatile aromas in Thai colored rice cultivars

“…Among these, hydrocarbons and aldehydes account for the greatest proportion by weight of volatile constituents in rice (Lin et al, 2010). The hydrocarbons found in rice include 2,6,10-trimethyldodecane, pentadecane, 2,6,10-trimethylpentadecane, hexadecane, and heptadecane, while the aldehydes include pentanal, hexanal, heptanal, 2-heptene aldehyde, octanal, nonanal, decyl aldehyde, 2-methypropanal, 2methylbutanal, 3-methylbutanal and benzene formaldehyde (Yang et al, 2008;Lin et al, 2010;Zheng et al, 2022). Among alcohols, 1octen-3-ol, hexanol, and 1-octanol have been considered to be more abundant compounds than the aldehydes (Yang et al, 2008).…”