Non-conventional starches for biodegradable films: A review focussing on characterisation and recent applications in food

Starch biopolymer films containing chitosan nanoparticles: A review

Starch biopolymer films incorporated with chitosan nanoparticles (CNP) or starch/CNP films are promising alternatives to non-degradable food packaging materials. The films can be utilized for active food packaging applications because CNP exhibits antimicrobial and antioxidant properties, which can improve food shelf-life. Nonetheless, knowledge of the effects of CNP inclusion on the properties of starch films is not fully elucidated. This paper reviews the influences of various concentrations of CNP, sizes of CNP, and other additives on the mechanical, thermal, barrier, antimicrobial, antioxidant, biodegradability, and cytotoxicity properties of starch/CNP films as well as the mechanisms involved in relation to food packaging applications. The usage of starch/CNP films for active food packaging can help to reduce environmental issues and contribute to food safety and security.

Loquat seed starch - Emerging source of non-conventional starch: Structure, properties, and novel applications

Recently, non-conventional sources of starch have attracted attention due to their potential to provide cost-effective alternatives to traditional starch. Among non-conventional starches, loquat (Eriobotrya japonica) seed starch is an emerging source of starch consisting of the amount of starch (nearly 20 %). Due to its unique structure, functional properties, and novel applications, it could be utilized as a potential ingredient. Interestingly, this starch has similar properties as commercial starches including high amylose content, small granule size, and high viscosity and heat stability, making it an attractive option for various food applications. Therefore, this review mainly covers the fundamental understanding of the valorization of loquat seeds by extracting the starch using different isolation methods, with preferable structural, morphological, and functional properties. Different isolation and modification methods (wet milling, acid, neutral and alkaline) are effectively used to obtain higher amounts of starch are revealed. Moreover, insight into various analytical techniques including scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction used to characterize the molecular structure of the starch are discussed. In addition, the effect of shear rate and temperature on rheological attributes with solubility index, swelling power, and color is revealed. Besides, this starch contains bioactive compounds that have shown a positive impact on the enhancement of the shelf-life of the fruits. Overall, loquat seed starches have the potential to provide sustainable and cost-effective alternatives to traditional starch sources and can lead to novel applications in the food industry. Further research is needed to optimize processing techniques and develop value-added products that can be produced at a large scale. However, there is relatively limited published scientific evidence on the structural and morphological characteristics of loquat seed starch. Thus, in this review, we focused on different isolation techniques of loquat seed starch, its structural and functional characteristics, along with potential applications.

Influence of Ulluco Starch Modified by Annealing on the Physicochemical Properties of Biodegradable Films

This work aimed to evaluate the use of annealing (ANN) ulluco starch in the preparation of biodegradable films and its impact on the physicochemical properties of the materials. Three film samples (FS1, FS2, and FS3) were prepared at a fixed starch concentration (2.6% w/v) using glycerol as a plasticizer and then compared to a control sample (FSC) prepared with native ulluco starch. The physical, mechanical, and thermal properties of the films were evaluated. The use of ANN starch decreased the solubility (from 21.8% to 19.5%) and the swelling power (from 299% to 153%) of the film samples. In addition, an increase in opacity and relative crystallinity (from 7.54% to 10.5%) were observed. Regarding the thermal properties, all the samples presented high stability to degradation, with degradation temperatures above 200 °C. However, the samples showed deficiencies in their morphology, which affected the barrier properties. The use of ANN starch has some advantages over native starch in preparing films. However, more analysis is needed to improve the barrier properties of the materials. This work reveals the potential of the ANN ulluco starch for biodegradable film preparation. In addition, the use of modified ulluco starch is an alternative to add value to the crop, as well as to replace non-biodegradable materials used in the preparation of packaging.

Octenyl Succinic Anhydride Modified Pearl Millet Starches: An Approach for Development of Films/Coatings

Pearl millet starches were modified at pH 8.0 using 3.0% octenyl succinic anhydride (OSA), and their pasting, rheological properties, and in vitro digestibility were analyzed. The degree of substitution (D.C.) of OSA-modified starches varied from 0.010 to 0.025. The amylose content decreased after modification, while the reverse was observed for swelling power. After OSA modification, the pasting viscosities (peak, trough, setback (cP)) of the modified starches increased compared to their native counterparts. G′ (storage modulus) and G″ (loss modulus) decreased significantly (p < 0.05) compared to their native counterparts during heating. Yield stress (σo), consistency (K), and flow behavior index (n) varied from 9.8 to 87.2 Pa, 30.4 to 91.0 Pa.s., and 0.25 to 0.47, respectively. For starch pastes, steady shear properties showed n < 1, indicating shear-thinning and pseudoplastic behavior. The readily digestible starch (RDS) and slowly digestible starch (SDS) contents decreased, while the resistant starch (R.S.) content increased. After OSA treatment, the solubility power of the starches increased; this property of OSA starches speeds up the biodegradability process for the films, and it helps to maintain a healthy environment.

Cassava-Starch-Based Films Incorporated with Buriti (Mauritia flexuosa L.) Oil: A New Active and Bioactive Material for Food Packaging Applications

The objective of this study was to develop and characterize cassava-starch-based films incorporated with buriti (Mauritia flexuosa L.) oil and emulsifier (Tween 20). An experimental factorial design 22 with three central points was used to develop the films, by varying the concentrations of buriti oil (0.15 to 0.45% w/v) and emulsifier (0.02 to 0.04% w/v). Film thickness and weight increased with increasing buriti oil concentration. The water vapor permeability of the films ranged from 0.22 to 0.366 g mm h−1 m−2 kPa−1. The tensile strength values varied from 4.21 to 6.95 MPa, the elasticity modulus varied from 538.53 to 722.78 MPa, and elongation to rupture varied from 1.13 to 1.66%. The film color was characterized as yellowish, dark, and intense (higher oil content); and clear and a low-intensity color (lower oil content). The films presented a total carotenoid content ranging from 3.63 to 29.73 μg β-carotene/g, which may have resulted in their antioxidant potential against DPPH• (1,1-diphenyl-2-picryl-hydrazyl) radical (from 74.28 to 87.74%). The central formulation of the experimental design (buriti oil 0.30% and emulsifier 0.03%) presented a good performance and can be applied as packaging for foods with a lower water content and that demand protection against oxidation.