Optimization of phenolic compounds extraction and a study of the edaphic effect on the physicochemical composition of freeze-dried jaboticaba peel

ABSTRACT Jaboticaba is a fruit with high nutritional potential with beneficial effects for health. The aims of this work were the optimization of the extraction of phenolic compounds (PhC) from freeze-dried jaboticaba peel (FJP) as a function of the stirring time (ST) and solvent volume (SV) and to study the edaphic effect on the physical-chemical composition of FJP from five orchards. In the first stage, a 2-factor, 2-level central composite designs combined with the Response Surface Methodology and desirability function was used. In the second stage, a one-way analysis of variance was used to investigate the edaphic effect on the responses. Total phenols (Tph), tannins (Ta), total monomeric anthocyanins (TMA), color index (CI) and tone responses (Ton) were analyzed. A second-order polynomial model was used for predicting of the first stage dates. The data from the second experiment were evaluated using analysis of variance, Tukey’s test, and t-test. The optimal conditions for the PhC were 64 mL and 75 min. Under the optimum conditions, the corresponding predicted response values for PhC were 33.5, 7.91, and 5.57 mg g-1 and 0.893 u.a. and 0.833 for Tph, Ta, TMA, CI, and Ton, respectively. According to the type of soil, different PhC values were found in FJP extracts. In nutrient-poor soils, highest levels of PhC, high CI and low tone were found.

摘要：嘉宝果（Jaboticaba）是一种兼具高营养潜力与健康益处的水果。本研究旨在实现两大研究目标：一是以搅拌时间（stirring time, ST）和溶剂体积（solvent volume, SV）为考察因素，优化冻干嘉宝果皮（freeze-dried jaboticaba peel, FJP）中酚类化合物（phenolic compounds, PhC）的提取工艺；二是探究土壤效应对5个果园来源的FJP理化成分的影响。第一阶段实验采用二因素二水平中心复合设计，结合响应面法（Response Surface Methodology, RSM）与期望函数法；第二阶段则采用单因素方差分析，以评估土壤因素对各响应指标的影响。本研究检测的响应指标包括总酚（total phenols, Tph）、单宁（tannins, Ta）、总单体花青素（total monomeric anthocyanins, TMA）、色泽指数（color index, CI）以及色调响应（tone responses, Ton）。第一阶段实验通过二阶多项式模型对提取数据进行预测；第二阶段的实验数据则通过方差分析、Tukey检验与t检验开展统计评估。酚类化合物提取的最优工艺条件为溶剂体积64 mL、搅拌时间75 min；在此最优条件下，各响应指标的预测值分别为：总酚33.5 mg·g⁻¹、单宁7.91 mg·g⁻¹、总单体花青素5.57 mg·g⁻¹，色泽指数0.893 u.a.，色调响应0.833。研究结果表明，不同种植土壤来源的FJP提取物中酚类化合物含量存在显著差异：在养分贫瘠的土壤中种植的嘉宝果，其FJP提取物的酚类化合物总量更高、色泽指数更大，且色调值更低。