制备工艺对番茄皮膳食纤维理化性质的影响

以番茄酱加工剩余物番茄皮为原料，采用酸法、碱法、酸碱结合法和酶- 酸法4 种工艺制备番茄皮膳食纤维并对其理化性质进行分析。4 种工艺中，酶- 酸法工艺去除杂质效果最好，所得产品可溶性纤维含量最高(8.23%)、纯度最高(92.01%)、产品色泽最佳。4 种方法制备的膳食纤维与原料在组成和理化性质上有很大差异。酸碱结合法和碱法制备的膳食纤维有较高的持水力(分别为8.74、7.85g/g)和膨胀力(分别为5.5、4.9mL/g)，而酶- 酸法和酸法制备的膳食纤维有较高的持油力(分别为5.91、5.49g/g)和吸附胆酸钠的能力(分别为329.4、297.3mg/g)。除酶- 酸法外，其他方法制备的膳食纤维的阳离子交换能力均比原料高。

Effects of Different Extraction Processes on the Physico-chemical Properties of Tomato Skin Dietary Fiber

Four different extraction processes, namely sulfuric acid treatment, sodium hydroxide treatment, sequential treatment with sulfuric acid followed by sodium hydroxide and sequential treatment with trypsin followed by sulfuric acid were used to obtain total dietary fiber (TDF) from tomato skin, a byproduct of the tomato paste industry. The physicochemical properties (waterholding capacity, oil-holding capacity, swelling capacity, cation-exchange capacity and bile salt adsorption capacity) of the obtained TDF products were determined. Among the four extraction processes, sequential treatment with trypsin followed by sulfuric acid gave the best removal of impurities and the resultant product presented the highest soluble dietary fiber content and the best color. The proximate chemical composition and physico-chemical properties of the TDF products obtained using the four extraction processes were obviously different from those of the raw material. Both the TDF products obtained by sodium hydroxide treatment alone and in combination with sulfuric acid treatment had higher water-holding capacity (7.85 g/g and 8.7 4 g/g, respectively) and swelling capacity (4.9 mL/g and 5.5 mL/g, respectively), and the oil-holding and bile salt adsorption capacities of those obtained by sulfuric acid treatment alone and in combination with trypsin treatment were both high, reaching up to 5.49 g/g and 5.91 g/g, and 297.3 mg/g and 329.4 mg/g, respectively. Except sequential treatment with trypsin followed by sulfuric acid, all the three other extraction processes yielded TDF products with a cation exchange capacity higher than that of the raw material.