Abstract:The sugar content and the matrix always are being changed during cider-making fermentation. In order to measure and monitor sugar content accurately and rapidly, it is necessary for the spectra to be sorted. Calibration models were established at different fermentation stages based on near infrared spectroscopy with artificial neural network. NIR spectral data were collected in the spectral region of 12 000-4 000 cm-1 for the next analysis. After the different conditions for modeling sugar content were analyzed and discussed, the results indicated that the calibration models developed by the spectral data pretreatment of straight line subtraction(SLS) in the characteristic absorption spectra ranges of 7 502-6 472.1 cm-1 at stageI and 6 102-5 446.2 cm-1 at stageⅡ were the best for sugar content. The result of comparison of different data pretreatment methods for establishing calibration model showed that the correlation coefficients of the models (R2) for stageI and Ⅱ were 98.93% and 99.34% respectively, and the root mean square errors of cross validation(RMSECV) for stageI and Ⅱ were 4.42 and 1.21 g·L-1 respectively. Then the models were tested and the results showed that the root mean square error of prediction (RMSEP) was 4.07 g·L-1 and 1.13 g·L-1 respectively. These demonstrated that the models the authors established are very well and can be applied to quick determination and monitoring of sugar content during cider-making fermentation.
Key words:Near infrared spectroscopy;Cider;Sugar content;Artificial neural network;Partial least square
[1] Blanco M, Villarroya I. Trends in Analytical Chemistry, 2002, 21(4): 240. [2] José Lúis Moreira, Lúcia Santos. Analytica Chimical Acta, 2004, 513: 263. [3] Urbano-Cuadrado M, Luque de Castro M D, Perez-Juan P M, et al. Analytica Chimical Acta, 2004, 527: 81. [4] Cozzolino D, Kwiatkowski M J, Parker M, et al. Analytica Chimica Acta, 2004, 513: 73. [5] PENG Bang-zhu, LONG Ming-hua, YUE Tian-li, et al(彭帮柱, 龙明华, 岳田利, 等). Transations of Chinese Society Agricultural Engineering(CSAE)(农业工程学报), 2006, 22(12): 216. [6] CHEN Bin, WANG Hao, LIN Song, et al(陈 斌, 王 豪, 林 松, 等). Transations of Chinese Society Agricultural Engineering(CSAE)(农业工程学报), 2005, 21(7): 99. [7] GUO Xin-guang, MA Pei-xuan, REN Yi-ping(郭新光, 马佩选, 任一平). GB/T 15038—2005. Analytical Methods of Wine and Fruit Wine(GB/T 15038—2005葡萄酒、果酒适用分析方法). Beijing: Chinese Standards Press(北京: 中国标准出版社), 2005. [8] LI Dai-xi, WU Zhi-yong, XU Duan-jun, et al(李代禧, 吴智勇, 徐端钧, 等). Chinese Journal of Analytical Chemistry(分析化学), 2004, 32(8): 1070. [9] Fredric M Ham, Ivica Kostanic. Principles of Neurocomputing for Science and Engineering. Beijing: China Machine Press, 2003. [10] LU Wan-zhen, YUAN Hong-fu, XU Guang-tong, et al(陆婉珍, 袁洪福, 徐广通, 等). Modern Near Infrared Spectroscopy Analysis Technique(现代近红外光谱分析技术). Beijing: Chinese Press of Petroleum Chemical Industry(北京: 中国石油化工出版社), 2000. [11] Larrechi M, Callao M. Trends Anal. Chem., 2003, 22: 634. [12] XU Gang-tong, LU Wan-zhen, YUAN Hong-fu(徐广通, 陆婉珍, 袁洪福). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2001, 21(4): 459. [13] YUAN Cen-ren(袁曾任). Artificial Neural Networks and Applications(人工神经元网络及应用). Beijing: Tsinghua University Press(北京: 清华大学出版社), 2003.