Physico-chemical variability of cassava flour in the Território da Cidadania do Vale do Juruá, Acre

ABSTRACT The flour is a processed cassava food of great dietary importance, but with little standardization due to the craft manufacturing process. The aim of this study was to analyze the variability of artisanal cassava flour produced in Território da Cidadania do Vale do Juruá, Acre, and group the producing municipalities according to physico-chemical characteristics using multivariate analysis todetermine their influence on the flour quality. A total of 138 flour samples were collected in the cities of Cruzeiro do Sul, Mâncio Lima, Rodrigues Alves, Porto Walter and Marechal Thaumaturgo. Moisture, ash, total protein, ether extract, total fiber, total carbohydrate, energy value, titratable acidity, pH and water activity were determined in the samples. Data were analyzed using descriptive statistics and means compared with the Tukey test. and multivariate statistics in a complementary way, hierarchical cluster analysis with Euclidean distance and Ward method, and non-hierarchical, k-means, principal components analysis with correlation matrix, and backward stepwise discriminant analysis. The results showed that the flours met the quality standards required by the legislation. The different multivariate analyzes were consistent, indicating that the physico-chemical properties of the flours have a pattern of distribution, which suggests standards in the manufacturing process distributed according to the location of the municipalities analyzed. The most influencing characteristics for flour discrimination are acidity, pH, water activity and moisture, indicating that the mode of production has great influence on the quality of the flour produced.

摘要 木薯粉是一类具有重要膳食价值的加工木薯制品，但受手工制作工艺限制，相关产品标准仍较为匮乏。本研究旨在对巴西阿克雷州（Acre）茹鲁阿谷公民领地（Território da Cidadania do Vale do Juruá）所产手工木薯粉的变异性展开分析，并基于理化特性通过多变量分析（multivariate analysis）对各生产市镇进行聚类，以明确其对木薯粉品质的影响。
研究共在克鲁塞罗杜苏伊（Cruzeiro do Sul）、曼西奥利马（Mâncio Lima）、罗德里格斯阿尔维斯（Rodrigues Alves）、波尔图沃尔特（Porto Walter）以及马雷夏尔托马图尔戈（Marechal Thaumaturgo）5座市镇采集了138份木薯粉样品。对所有样品的水分（moisture）、灰分（ash）、总蛋白（total protein）、乙醚提取物（ether extract，即粗脂肪）、总纤维（total fiber）、总碳水化合物（total carbohydrate）、能量值（energy value）、滴定酸度（titratable acidity）、pH值以及水分活度（water activity）进行了测定。
采用描述性统计学方法对数据进行分析，均值比较采用Tukey检验（Tukey test），并辅以多变量统计分析：包括基于欧氏距离（Euclidean distance）与沃德法（Ward method）的分层聚类分析（hierarchical cluster analysis）、非分层的K均值聚类（k-means）、基于相关矩阵（correlation matrix）的主成分分析（principal components analysis），以及向后逐步判别分析（backward stepwise discriminant analysis）。
结果显示，所检测的木薯粉均符合相关法规要求的质量标准。不同多变量分析方法结果一致，表明木薯粉的理化特性存在分布规律，这暗示各生产市镇的木薯粉制作工艺标准存在地域分布特征。对木薯粉区分度影响最大的特性为酸度、pH值、水分活度与水分，说明生产方式对所产木薯粉的品质具有显著影响。