The formation mechanism, analysis strategies and regulation measures of cereal aroma: A review

Cereal food is widely consumed mainly as the staple food of people. As a decisive factor that directly affects the quality evaluation and consumer acceptance of cereals, aroma has been paid increasing attention. Currently, the research on the formation mechanism and regulation measures of cereal aroma is still weak. Strategies of aroma analysis are constantly updated. Thus, it is necessary to systematically review the research status in the field of cereal aroma. The main volatile compounds, and their formation mechanisms, traditional and emerging analysis strategies, and regulation measures in cereals were reviewed. Significant variability of volatile compounds has been observed between different cereal varieties, and between raw cereals and their processed products. Overall, aldehydes, heterocyclic compounds and alcohols contributed more to their overall aroma. The formation of cereal aroma is a complex process, which mainly includes genetic factors, Maillard reaction (MR), caramelization reaction (CR), degradation of lipids, amino acids and proteins, microbial metabolism, and their interactions. Currently, accurate, fast, safe, real-time and non-destructive analysis technologies combined with machine learning (ML) has been used in the identification, evaluation and prediction of cereal aroma, and the outcome is better than the traditional methods. The adjustment of precursor substances and reaction conditions, addition of exogenous additives and adoption of emerging processing technologies are the commonly used aroma regulation measures. Apart from the evaluation and prediction of aroma, ML has also realized the direct and indirect synthesis of desirable aroma, which is a new trend of aroma regulation in cereals.