Maphosa Yvonne, Jideani Victoria Adaora, Ikhu-Omoregbe Daniel Imwansi
Department of Food Science and Technology, Cape Peninsula University of Technology, P.O. Box 1906, 7535 Bellville, South Africa.
Department of Chemical Engineering, Cape Peninsula University of Technology, P.O. Box 1906, 7535 Bellville, South Africa.
Food Technol Biotechnol. 2022 Sep;60(3):361-374. doi: 10.17113/ftb.60.03.22.7409.
Bambara groundnut ( (L.) Verdc.) is a great source of soluble dietary fibre and starch. Bambara groundnut soluble dietary fibre is rich in bioactive compounds, namely, uronic acids (11.8%) and hydrolysable polyphenols (expressed as gallic acid equivalents (GAE) 20 mg/g), with crucial physiological and functional benefits. The industrial use of native starch is limited because of the inherent undesirable attributes that render it unstable. The aim of this study is to characterise the antioxidant, functional and physicochemical properties of Bambara groundnut starch-soluble dietary fibre nanocomposite (hereafter groundnut nanocomposite).
The pasting properties by rapid visco analysis, chemical composition, hydration properties, oil-binding capacity, emulsifying activity index (EAI), emulsion stability index (ESI) and antioxidant properties of Bambara groundnut starch, soluble fibre and nanocomposite were studied.
The Bambara groundnut soluble dietary fibre and nanocomposite did not exhibit typical pasting properties. The nanocomposite had high mass fraction of carbohydrates (78.7%) and proteins (7.0%), low mass fraction of fat (0.8%) and had a considerable mass fraction of ash (4.9%). The Bambara groundnut starch, soluble dietary fibre and nanocomposite showed significant (p<0.001) differences in solubility. Their EAI values were 23.2, 85.7 and 90.6%, respectively, and the ESI values were 23.3, 87.1 and 87.5%, respectively. The three biopolymers differed significantly (p<0.001) in all colour characteristics: lightness (), redness/greenness (), yellowness/blueness (*), chroma and hue angles. Their polyphenolic mass fraction, expressed as GAE, was 0.10, 6.6 and 0.46 mg/g, respectively, and their ferric reducing antioxidant power values, expressed as ascorbic acid equivalents (AAE), were 1.2, 4.8 and 1.4 μmol/g, respectively. The phenolic compounds (in mg/g): chlorogenic acid 18, monocrotaline 20, luteolin 7-O-(6''-malonylglucoside) 4 and casuarine 6-α-d-glucoside 27 were present in the dietary fibre but absent from the starch and nanocomposite. The Bambara groundnut nanocomposite possesses desirable physicochemical and antioxidant properties, making it suitable as an ingredient in various food systems.
Nanocomposites have the potential to revolutionise the food industry but their study as food ingredients is very limited. Furthermore, nothing is known about the physicochemical, functional and antioxidant characteristics of Bambara groundnut nanocomposite, thus investigating these properties will address this knowledge gap.
非洲竹芋（Voandzeia subterranea (L.) Verdc.）是可溶性膳食纤维和淀粉的重要来源。非洲竹芋可溶性膳食纤维富含生物活性化合物，即糖醛酸（11.8%）和可水解多酚（以没食子酸当量（GAE）表示为20毫克/克），具有重要的生理和功能益处。天然淀粉的工业用途有限，因为其固有的不良特性使其不稳定。本研究的目的是表征非洲竹芋淀粉 - 可溶性膳食纤维纳米复合材料（以下简称竹芋纳米复合材料）的抗氧化、功能和物理化学性质。
研究了非洲竹芋淀粉、可溶性纤维和纳米复合材料的快速粘度分析糊化特性、化学成分、水化特性、油结合能力、乳化活性指数（EAI）、乳化稳定性指数（ESI）和抗氧化性能。
非洲竹芋可溶性膳食纤维和纳米复合材料未表现出典型的糊化特性。纳米复合材料的碳水化合物质量分数高（78.7%），蛋白质质量分数高（7.0%），脂肪质量分数低（0.8%），灰分质量分数可观（4.9%）。非洲竹芋淀粉、可溶性膳食纤维和纳米复合材料在溶解度方面存在显著差异（p<0.001）。它们的EAI值分别为23.2%、85.7%和90.6%，ESI值分别为23.3%、87.1%和87.5%。这三种生物聚合物在所有颜色特征方面均存在显著差异（p<0.001）：明度（L）、红度/绿度（a）、黄度/蓝度（b）、色度和色相角。它们以GAE表示的多酚质量分数分别为0.10毫克/克、6.6毫克/克和0.46毫克/克，以抗坏血酸当量（AAE）表示的铁还原抗氧化能力值分别为1.2微摩尔/克、4.8微摩尔/克和1.4微摩尔/克。膳食纤维中存在酚类化合物（毫克/克）：绿原酸18、农吉利碱20、木犀草素7 - O -（6'' - 丙二酰葡萄糖苷）4和桤木酮6 - α - D - 葡萄糖苷27，而淀粉和纳米复合材料中不存在。非洲竹芋纳米复合材料具有理想的物理化学和抗氧化性能，使其适合作为各种食品体系的成分。
纳米复合材料有潜力彻底改变食品工业，但作为食品成分的研究非常有限。此外，关于非洲竹芋纳米复合材料的物理化学、功能和抗氧化特性一无所知，因此研究这些特性将填补这一知识空白。
