Acacia Gum as a Natural Anti-Plasticizer for the Production of Date Syrup Powder: Sorption Isotherms, Physicochemical Properties, and Data Modeling.

The thermoplastic and hygroscopic behaviors of date syrup (DS) challenge the DS drying process. In this context, DS was mixed with 30%, 40%, 50%, and 60% acacia gum (AG) and subjected to a drum dryer. The chemical composition, bulk density (pb), caking degree (CD), glass transition temperature (Tg), and color values of DS powders were studied. The sorption isotherms were also obtained and compared to that of those predicted by mathematical models. According to the results, increasing the AG concentration enhanced the moisture content, pb, brightness, and Tg while it reduced the CD and equilibrium moisture sorption. All DS powders had type III isotherm behavior, i.e., similar to high-sugar foods. Guggenheim-Anderson-de Boer (GAB) and Peleg models were found to be suitable for fitting the experimental data and these models explained the monolayer moisture content decrease with increasing AG concentration. These results of the present study, for the first time, verified that the AG can be used as a natural anti-plasticizer agent for DS powder production.

Water resistance and mechanical properties of low methoxy-pectin nanocomposite film responses to interactions of Ca2+ ions and glycerol concentrations as crosslinking agents.

To achieve a low methoxy-pectin nanocomposite film with maximum resistance to water and acceptable mechanical properties, the interactions of different glycerol concentrations and Ca2+ ions in both steps of crosslinking on the swelling degree (SD) and mechanical properties of prepared films were investigated using response surface methodology (RSM). Accordingly, quadratic second-order models were fitted to the SD and tensile strength responses; while the cubic model demonstrated a good relation between independent variables and elongation at break respectively. As a compromise between water resistance and mechanical properties of the prepared films, the use of 0.5% Ca2+, 0.75% Gly1 and 7.5% Gly2 is suggested as the optimum condition. Generally, crosslinking of pectin polymer with Ca2+ cations in the second step along with incorporation of nanocellulose into pectin film led to the formation of more flexible and completely water insoluble pectin nanocomposite film in comparison to the other polymers crosslinked with Ca2+ cations.

Preparation and characterization of a novel bionanocomposite edible film based on pectin and crystalline nanocellulose.

In this study, for the first time, the edible pectin film was reinforced by crystalline nanocelullose (CNC). The incorporation of three levels of CNC (2, 5 and 7% w/w) on mechanical, thermal and water vapor barrier properties of pectin-based biodegradable film were investigated using solution casting evaporation method for film preparation. The optimum result was obtained through the nanocomposite film with 5% CNC in terms of mechanical and water vapor properties as the tensile strength increased up to 84% and water vapor permeability decreased by 40%. However, analysis of thermal properties indicated no significant effect of CNC on glass transition temperature. X-ray diffraction (XRD) studies illustrated a positive correlation between the degree of crystallinity and the CNC level. Moreover, AFM images presented good dispersion of CNC in the pectin matrix suggesting appropriate interaction between the filler and matrix, which is in agreement with mechanical consequences. According to the overall results, the reinforcement of pectin film with 5% CNC compared to other strengthening strategies had a higher effect and therefore it could be introduced as a good candidate for the development of strong, completely biodegradable and renewable food packaging material.

Recent innovations in the area of edible films and coatings.

Edible films/coatings have been considered as one of the potential technologies that can be used to increase the storability of foods and to improve the existent packaging technology, helping to ensure the microbial safety and the preservation of food from the influence of external factors. Innovations constantly appear in food packaging, always aiming at creating a more efficient quality preservation system while improving foods' attractiveness and marketability. The utilization of renewable sources for packaging materials, such as hydrocolloids and lipids from biological origin, is one the main trends of the industry. These films should have acceptable sensory characteristics, appropriate barrier properties (CO2, O2, water, oil), microbial, biochemical and physicochemical stability, they should be safe, and produced by simple technology in low cost. Also they can act as effective carrier for antioxidant, flavor, color and nutritional or anti-microbial additives. Nowadays, a great discussion exists about the potential applications of edible films/coatings on food products. The general trend is to find the correct combination between the food product and the edible film/coating, which will ensure the success of the technology.

Use of edible films and coatings to extend the shelf life of food products.

The increased consumer demand for high quality, extended shelf life, ready to eat foods has initiated the development of several innovative techniques to keep their natural and fresh appearance as long as possible and at the same time render them safe. Packaging has been an important element in these preservation concepts for providing the appropriate (mechanical and functional) protection to the commodity. Since synthetic packaging materials contribute to the environmental pollution, edible coatings and packages have been proposed to replace or complement conventional packaging. Biodegradable and edible films and coatings are made from naturally occurring polymers and functional ingredients, and formed on the surface of food products. Edible films and coating have long been known to protect perishable food products from deterioration and reduce quality loss. These films should have acceptable sensory characteristics, appropriate barrier properties (CO(2), O(2), water, oil), microbial, biochemical and physicochemical stability, they should be safe, and be produced by simple technology in low cost. Also they can act as effective carrier for antioxidant, flavor, color, nutritional or anti-microbial additives. Patents on edible films and food products are also discussed in this article.

Enthalpy relaxation of bovine serum albumin and implications for its storage in the glassy state.

Two endothermic peaks could be observed for five commercial samples of bovine serum albumin (BSA). The smaller peak observed by differential scanning calorimetry (DSC) corresponded to enthalpy relaxation. This peak was followed on storage of BSA, in its glassy state, after it had been heated above its denaturation temperature. Enthalpy and peak temperature increased with duration of storage. On storage for one week at 60 degrees C, a sample at 8.3% moisture showed a peak at 100 degrees C with an energy value of approximately 2 J per g protein. BSA samples were heated within the DSC sufficiently to eliminate the lower enthalpy peak but without altering the denaturation enthotherm. The amount of physical aging shown by these BSA samples was similar to that of the heat-denatured samples. It was concluded that the heating endotherms of dry BSA reflect both the storage and thermal history of the sample. Possible implications of the enthalpy relaxation of BSA on the behavior of this important protein are considered.