Characterization of red ginseng residue protein films incorporated with hibiscus extract

Plant protein-based edible films and the effect of phenolic additives

The use of protein-based films in food preservation has been investigated as an alternative to synthetic plastics in recent years. Being biodegradable, edible, natural, and upcycling from food waste/by-products are the benefits of protein-based edible films. Their use ensures food safety as an alternative to synthetic plastics, and their film-forming properties can be improved with the addition of bioactive compounds. This review summarizes the studies on the changes in certain quality parameters of plant protein-based films, including mechanical, physicochemical, or morphological properties with the use of different forms of phenolic additives (pure phenolics, phenolic extracts, essential oils) and their application in foods during storage. Phenolics affect protein film matrix formation by acting as plasticizers or cross-linking agents and confer additional health benefits by providing bioactive properties to protein films. On the other hand, the effects were more pronounced with the use of their oxidized forms or higher concentrations. Consequently, phenolic additives have great potential to improve protein films, but further studies are still required to investigate the effects and mechanisms of phenolic addition to the protein-based films.

Pectin-based color indicator films incorporated with spray-dried Hibiscus extract microparticles

Colorimetric films incorporated with anthocyanins as an indicator for freshness monitoring have aroused growing interest recently. The pH-sensing colorimetric film were developed based on pectin (HM), containing aqueous hibiscus extract microparticles (HAE). HAE microparticles were obtained by spray drying with different wall materials (Inulin -IN, maltodextrin- MD and their combination). The films were obtained on large scale by continuous casting. These films were characterized for physicochemical analysis, morphological structure, thermal and barrier properties, antioxidant activity, and color change at different pH. The addition of HAE microparticles caused relevant changes to HM-based films, such as in mechanical behavior and improved barrier property (11-22% WVTR reduction) depending on the type of wall material used and the concentration added. It was verified with the thermal stability of films, with a slight increase being observed. The color variation of smart films was entirely pH-dependent. Overall, the proposed color indicator films showed unique features and functionalities and could be used as an alternative natural pH indicator in smart packaging systems.

Characterisation and Antibacterial Properties of Novel Biodegradable Films Based on Alginate and Roselle (Hibiscus sabdariffa L.) Extract

Composite films were prepared with alginate and roselle extract (HE) at different concentrations (1%, 3%, and 5% w/v) via solvent casting technique and analyzed in terms of physical, mechanical, and antibacterial properties. The incorporation of HE into alginate films resulted in rough and heterogeneous surface characteristics with increasing concentrations of HE. The thickness and water vapor permeability of alginate-HE composite films were significantly higher (p < 0.05) compared to pure alginate films. Moreover, water content, solubility, swelling, tensile strength, and elongation at break value of the composite films decreased (p < 0.05) with increasing concentrations of the extract. FTIR spectra revealed shifts and intensity variations in the composite films and the formation of new peaks suggesting a possible interaction between alginate and HE. Alginate-HE films exhibited good antibacterial activity against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacteria. The antibacterial effect of the films, more pronounced against Gram-positive bacteria, increased with higher amounts of HE. The resulting films may be utilised as new biodegradable, antibacterial films in the food packaging industry to prolong shelf life and preserve food safety.

Graphical Abstract

Supplementary Information

The online version of this article (10.1007/s12649-022-01710-3) contains supplementary material, which is available to authorized users.

Physicochemical characteristics and sensory acceptability of crackers containing red ginseng marc

Red ginseng marc (RGM), a by-product from ginseng industry, still contains bioactive compounds such as ginsenosides and dietary fibers. The objective of this study was to investigate effects of baking conditions and formulations on physicochemical and sensory characteristics of crackers in which RGM was incorporated. The sum of ginsenoside Rb1, Rg1 and Rg3 (58.69 ± 2.93 mg/100 g, dry basis) and dietary fibers (7.52 ± 1.22 g/100 g) were the highest in the crackers baked at 120 °C for 60 min. The crackers with 5% replacement of wheat flour with RGM scored the highest in taste and overall acceptability. The baked crackers still contained relatively high amounts of ginsenoside Rb1 (7.62 ± 0.34 mg/100 g), Rg3(R) (7.51 ± 0.99 mg/100 g) and Rg3(S) (8.65 ± 0.77 mg/100 g) and dietary fiber (2.59 ± 0.17 g/100 g). The results suggest that low temperature-long time may be a suitable baking condition to retain bioactive ginsenosides in RGM and using proper amount of RGM in bakery products may improve not only nutritional quality but also sensory properties.

Development of an antioxidative packaging film based on khorasan wheat starch containing moringa leaf extract

The aim of this study was to develop and characterize the properties of khorasan wheat starch (KWS) films containing moringa leaf extract (MLE) as an antioxidative packaging material. KWS was isolated from khorasan wheat and used as a film base material. Different amounts (0, 0.4, 0.7, and 1.0%, w/v) of MLE were added to the KWS film-forming solution and the film properties were examined. Tensile strength of the KWS films decreased and elongation at break increased with increasing MLE content. In addition, the KWS films containing MLE possessed good antioxidative activities and ultraviolet light blocking ability. In particular, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging abilities of the KWS films with 1.0% MLE were 59.45% and 37.89%, respectively. Moreover, KWS films containing 1.0% MLE were biodegradable within 30 days. These findings indicate that the developed KWS films containing MLE can be applied as a biodegradable packaging material with antioxidative activity.

Characterization of Barnyard Millet Starch Films Containing Borage Seed Oil

In this study, barnyard millet starch (BMS) was used to prepare edible films. Antioxidant activity was conferred to the BMS film by incorporating borage seed oil (BO). The physical, optical, and thermal properties as well as antioxidant activities of the films were evaluated. The incorporation of BO into the BMS films decreased the tensile strength from 9.46 to 4.69 MPa and increased the elongation at break of the films from 82.49% to 103.87%. Water vapor permeability, water solubility, and moisture content of the BMS films decreased with increasing BO concentration, whereas Hunter b value and opacity increased, L and a values of the films decreased. The BMS films containing BO exhibited antioxidant activity that increased proportionally with increased BO concentration. In particular, the BMS film with 1.0% BO exhibited the highest antioxidant activity and light barrier properties among the BMS films. Therefore, the BMS films with added BO can be used as an antioxidant packaging material.