Effect of Presence and Concentration of Plasticizers, Vegetable Oils, and Surfactants on the Properties of Sodium-Alginate-Based Edible Coatings

Abstract

Achieving high quality of a coated food product is mostly dependent on the characteristics of the food material to be coated, the properties of the components in the coating solution, and the obtained coating material. In the present study, usability and effectiveness of various components as well as their concentrations were assessed to produce an effective coating material. For this purpose, different concentrations of gelling agent (sodium alginate 0–3.5%, w/w), plasticizers (glycerol and sorbitol (0–20%, w/w), surfactants (tween 40, tween 80, span 60, span 80, lecithin (0–5%, w/w), and vegetable oils (sunflower oil, olive oil, rapeseed oil (0–5%, w/w) were used to prepare edible coating solutions. Formulations were built gradually, and characteristics of coatings were evaluated by analyzing surface tension values and its polar and dispersive components, emulsion droplet size, and optical appearance in microscopic scale. The results obtained showed that 1.25% sodium alginate, 2% glycerol, 0.2% sunflower oil, 1% span 80, and 0.2% tween 40 or tween 80 can be used in formulation to obtain an effective coating for hydrophobic food surfaces. Three formulations were designed, and their stability (emulsion droplet size, optical characteristics, and creaming index) and wettability tests on strawberry showed that they could be successfully used in coating applications.

The effects of different pre-treatments on the physicochemical composition and sensory acceptability of ‘Kacang Koro’ energy bar

“…This is in close agreement with the finding of Ndidi et al (2014) who also illustrated a significant reduction of crude fat in the Bambara groundnut when it is boiled. Similar findings were reported by Parreidt et al (2018), which the boiling treatment decreases the crude fat in the 'Kacang Koro' the most compared to toasting, soaking, and fermentation pre-treatment. Canavalia plagiosperma also showed a reduction of crude fat content when it was boiled (Alagbaoso et al, 2015), as they also convinced that the crude fat content decreased with increased processing time.…”

Alginate-Based Edible Films and Coatings for Food Packaging Applications

“…Therefore, the effects of the components on the surface tension of the coating solutions are an important factor. Yet, glycerol and sorbitol do not have a significant effect on the surface tension of the solutions due to not being tensio-active substances [ 87 , 88 ].…”

“…Adhesion on hydrophobic, rough surfaces and obtaining a uniform edible coating can be very difficult due to the low surface free energy of the surface [ 9 ]. Addition of surface active agents (surfactants) are the key ingredients to increase the wettability of the product and improve the adhesion of the coating material [ 88 ]. Moreover, with a reducing superficial water activity, surfactants and emulsifiers had a decreased rate of moisture loss when they were incorporated into the coating formulation [ 96 ].…”

“…Therefore, researchers checked the surface free energy of the food products, the surface tension of the edible coatings, and spreading coefficient (W s ) while designing their coating formulations. Senturk Parreidt, Schott, Schmid, and Müller [ 88 ] characterized the alginate-based coating formulations with various concentrations and types of surfactants (0–5% tween 40, tween 80, span 80, span 60, and soy lecithin).…”

The Development of a Uniform Alginate-Based Coating for Cantaloupe and Strawberries and the Characterization of Water Barrier Properties

“…The fruit leakage can be observed especially in fresh-cut melon, watermelon, pineapple, etc. The objective of this study is to evaluate the efficacy of the previously optimized alginate-based coating formulation [43] based on the water barrier properties of coated fresh produce, i.e., strawberry and fresh-cut cantaloupe. To this end, coating uniformity was achieved with the addition of an extra immersion step into a calcium lactate solution initially before the coating step.…”