Silva Sarah Maria Frota, Ribeiro Hálisson Lucas, Mattos Adriano Lincoln Albuquerque, Borges Maria de Fátima, Rosa Morsyleide de Freitas, de Azeredo Henriette Monteiro Cordeiro
Chemical Engineering Department, Federal University of Ceara, Campus Pici, Fortaleza, CE 60455-760 Brazil.
Embrapa Agroindústria Tropical, R. Dra. Sara Mesquita, 2270, Pici, Fortaleza, CE 60511-110 Brazil.
J Food Sci Technol. 2021 May;58(5):1979-1986. doi: 10.1007/s13197-020-04709-7. Epub 2020 Aug 17.
Cashew is a major crop in several tropical countries. Its cultivation is mostly aimed to the production of cashew nuts, whereas its byproducts (including cashew tree gum and cashew apples) are underutilized. In this study, cashew tree gum (CG) has been combined to nanofibrillated bacterial cellulose (NFBC) produced from cashew apple juice, at different ratios (from CG-only to NFBC-only), to produce edible films. While the CG-only dispersion (at 1 wt%) behaved as a quasi-Newtonian fluid, the addition of NFBC provided a shear-thinning behavior, making the dispersions easier to process, especially to cast. Moreover, the films containing increasing NFBC contents exhibited better physico-mechanical performance. When compared to the CG-only film, the films containing at least 25% NFBC presented remarkably higher strength and modulus (even similar to some conventional petroleum-derived polymers), lower water vapor permeability (WVP), and lower water solubility, although at the expense of lower elongation and higher opacity values. The combined use of both polysaccharides was demonstrated to be useful to overcome the limitations of both CG-only films (very low viscosity, poor tensile properties and very high WVP) and NFBC-only films (very high viscosity, making the dispersions difficult to mix and spread). Moreover, the use of different NFBC/CG ratios allow properties to be tuned to meet specific demands for different food packaging or coating purposes.
腰果是几个热带国家的主要作物。其种植主要旨在生产腰果，而其副产品（包括腰果树脂和腰果苹果）未得到充分利用。在本研究中，将腰果树脂（CG）与由腰果苹果汁生产的纳米纤化细菌纤维素（NFBC）以不同比例（从仅含CG到仅含NFBC）混合，以生产可食用薄膜。仅含CG的分散体（1 wt%）表现为准牛顿流体，而添加NFBC则呈现剪切变稀行为，使分散体更易于加工，尤其是流延。此外，NFBC含量增加的薄膜表现出更好的物理机械性能。与仅含CG的薄膜相比，至少含有25% NFBC的薄膜具有显著更高的强度和模量（甚至类似于一些传统的石油衍生聚合物）、更低的水蒸气透过率（WVP）和更低的水溶性，尽管牺牲了较低的伸长率和较高的不透明度值。结果表明，两种多糖的联合使用有助于克服仅含CG薄膜（极低粘度、较差的拉伸性能和非常高的WVP）和仅含NFBC薄膜（非常高的粘度，使分散体难以混合和铺展）的局限性。此外，使用不同的NFBC/CG比例可调节性能，以满足不同食品包装或涂层用途的特定需求。
