Electrospinning is a novel technique which has been used recently in the food field. Electrospun nanofibres (NF) have often been produced from non-edible compounds. Biopolymer solutions were developed from gelatin hydrolysed by bromelain in slightly acid medium (pH 4.5). The effects of gelatin concentration, bromelain activity and tip-collector distance on NF morphology and diameter (D_f) were studied. Defect-free NF were produced (no beads or droplets), having a 109.5 to 229.3 nm D_f. A Box-Behnken design was optimised for studying acetic acid’s effect on gelatin NF thermal behaviour and residual solvent concentration. Gelatin ionisation by acetic acid improved the solutions’ electrospinnability. NF denaturing temperature (T_d) was 98.4 °C and gelatin powder T_d 102.3 °C. These values were associated with smaller amorphous structure in NF than in gelatin powder. Total acetic acid became evaporated during electrospinning; solvent-free NF were thus produced in line with international food regulations.

中文翻译：

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水解明胶衍生，无溶剂的静电纺纳米纤维，可食用：物理，化学和热行为

电纺丝是一种新技术，最近已在食品领域中使用。电纺纳米纤维（NF）通常由不可食用的化合物制成。从菠萝蛋白酶在弱酸性介质（pH 4.5）中水解的明胶中开发出生物聚合物溶液。研究了明胶浓度，菠萝蛋白酶活性和吸头距离对NF形态和直径（D _f）的影响。产生无缺陷的NF（无珠或小滴），其D _f为109.5至229.3 nm 。对Box-Behnken设计进行了优化，以研究乙酸对明胶NF热行为和残留溶剂浓度的影响。用乙酸使明胶离子化可改善溶液的电纺丝性。NF变性温度（T _d）为98.4°C，明胶粉T_d 102.3°C。这些值与NF中的明胶粉末中较小的无定形结构有关。在静电纺丝过程中，总乙酸蒸发掉了。因此，根据国际食品法规生产了无溶剂NF。