Identification of Bitter and Astringent Components in Ma Bamboo Shoots and Their Relationship with Taste by Sensory Evaluation

The bitter and astringent substances in Ma bamboo shoots (Dendrocalamus latiflorus) were determined by quantitative analysis, and their relationship with taste was assessed by sensory evaluation. The fresh bamboo shoots were boiled at 100℃ for five different time periods i.e., 0, 30, 90, 150 and 420 s, respectively, and the residues and soups were measured for soluble tannin, oxalate and bitter amino acids (Phe, Val, Arg, Met and Leu), and sensory evaluation of bitter and astringent intensity by trained panelists. The bitterness and astringency of food-grade oxalic acid and tannin standard alone and their mixture at different concentrations were evaluated by sensory panelists to develop a characteristic function describing the relationship between concentration and taste intensity. The results showed that the bitter and astringent tastes of bamboo shoots was overwhelmingly ascribed to the presence of soluble tannin, and the relationship between both tastes and tannin was highly significant with a correlation coefficient of 0.896 and 0.867, respectively. The relationship between bamboo shoot astringency and oxalic acid was significant with a correlation coefficient of 0.448, but there was no significant relationship between bamboo shoot bitterness and oxalic acid. Moreover, no significant relationship existed between the two taste attributes and free bitter amino acids. The functions with tannin concentration as independent variable were used to explore the cause of the heavy bitterness and astringency of bamboo shoots. The results obtained from the analysis of nine samples showed that the models were reliable with a relevancy up to 60.6%-136.4% for astringency and 63.4%-132.0% for bitterness. The heavy bitterness and astringency of Dendrocalamus latiflorus was mainly caused by high contents of soluble tannin. © 2017, China Food Publishing Company. All right reserved.