The effect of packaging and storage time on quality of clustered fresh pistachio.

Pistachio is one of the valuable, very nutritious, and high-energy fruits that is mainly dried and used as a snack due to problems with storage. Therefore, to investigate on how to extend clustered fresh pistachios' shelf-life, the effects of various packaging and storage conditions on the pistachios are presented in this study. Thus, clustered in-hull fresh pistachios were packaged in: (a) Polyethylene film, 45 µm in thickness; (b) polypropylene/polyethylene/polyamide/polyethylene/aluminum foil multilayer film, 90 µm in thickness; (c) both films with alcoholic paper; in air, and under two gas mixtures of 88%N2 + 10%CO2 + 2%O2 and 83%N2 + 15%CO2 + 2%O2 . Samples were refrigerated at 5 ± 1°C for 3 months. Quality factors such as moisture content, weight loss, respiration rate, pH, texture, and appearance of the samples were monitored for fresh pistachio kernels and clustered pistachios. Data were analyzed in a completely randomized design using one-way analysis of variance. The results showed that the shelf-life of MAP samples drastically increased compared to the control (packages without gaseous and alcoholic paper). A comparison of means among the groups suggests that the multilayer bags of fresh clustered pistachios with a mixture of 83%N2 + 15%CO2 + 2%O2 for a 3-month storage period is a particularly effective treatment. PRACTICAL APPLICATION: It is the first time that fresh pistachio is packaged in clusters (bundle). It seems that the packaging of fresh pistachio clusters, in addition to the benefits mentioned in this paper has a psychological effect on the consumer in terms of the naturalness of this product and has added value due to being considered an organic, luxurious, and delicacy food product. Therefore, in this study, the active MAP method that includes the technique of injecting carbon dioxide, nitrogen, and oxygen into the packaging was used to investigate its effects on the properties and shelf-life of raw clustered pistachios for fresh consumption.

Optimization of biodegradable paper cup packaging coated with whey protein isolate and rice bran wax as potential popcorn package.

Biodegradable paper cups coated with rice bran wax and whey protein isolate were designed to package popcorn. Coatings with different concentrations of whey protein isolate (5.5, 7.75, and 10% w/v) and rice bran wax (0.2, 0.4, and 0.6% w/v) were applied on the outer surface of the paper cups. Thickness, color changes, Young's modulus and tensile strength, water vapor transmission rate (WVTR) of the coated and uncoated cups, and also popcorns properties (pH, texture, and sensory properties) were evaluated. Water vapor transmission rate, Young's modulus, thickness, total color change index, and tensile strength of coated cups with the optimal coating formulation was 19.785 (g/m2 day), 11.810 (MPa), 276.583 (µm), 1.839, and 11.222 (MPa), respectively. The results showed that paper cup coating increased thickness and yellowness and reduced the brightness, Young's modulus, and WVTR. Coating had a positive effect on the pH and texture of popcorns packaged in coated cups than samples packed in uncoated cups (p < .05). With increasing storage time due to moisture absorption, popcorn changes from crisp to viscoelastic and increases tissue firmness (p < .05). Popcorns' taste in uncoated cups had gained significantly lower scores by panelists compared with the samples packed in coated cups. There was a significant decrease in the general acceptance of popcorn during storage and also the type of coating used in the packaging cup (p < .05). Storage time and type of coating showed no significant effect on the moisture content, odor, and appearance of popcorn. In sensory evaluation, the coated packaging increased the taste, no difference in odor and appearance, and increased the overall acceptance of popcorn compared to the sample in uncoated cups. In general, the results showed that paper cup coating could be a new approach for barrier property improvement in paper-based food packaging and extending the shelf life of the products.

Production and evaluation of the chemical and mechanical properties of nanocellulose and nanowood starch-based biodegradable films potential candidates for moisture absorbers for food packaging.

This study was conducted to prepare starch-based moisture absorbent pads from nanocellulose (NC) and nanowood (NW) particles using solution casting evaporation method and to evaluate their physical and mechanical properties at different thicknesses. The swelling degree (SD), water vapor permeability (WVP), tensile strength (TS), and elongation at break (EB), of prepared biofilms were measured. Structural properties of biofilms were evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results indicated that two types of biopolymers showed the highest level of SD at thicknesses lower than 100 µm. The highest level of SD in the lowest time belonged to nanowood biofilm. Nanowood biofilms also showed highest WVP at lower thicknesses. Due to the highest EB and the lowest TS values, improvement was observed in mechanical properties of both nano biofilms. The high hydration capacity and WVP of low-thickness NW films make it a promising candidate for developing biodegradable films with the potential to be used as a moisture-absorbing pad in active food packaging.

Biodegradable zein film composites reinforced with chitosan nanoparticles and cinnamon essential oil: Physical, mechanical, structural and antimicrobial attributes.

Natural bio-based zein films were prepared by incorporating cinnamon essential oil (CEO) and chitosan nanoparticles (CNPs) at 2% and 4% (w/w) amounts, respectively, in order to provide mechanical and antimicrobial functionalities. The physical, mechanical, structural and antibacterial properties of the enriched zein films were also scrutinized. The results showed that the combination of CEO-CNPs significantly improves the tensile strength and decreases the elongation of zein film composite. According to X-ray diffraction (XRD) results, zein film experienced more crystallinity in the presence of CNPs and also combination of CNPs-CEO. Nano-scale size of CNPs and their uniform distribution within the zein film were monitored by scanning electron microscopy (SEM) and proved by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The antimicrobial properties were investigated against Escherichia coli and Staphylococcus aureus, observing that their growth was considerably inhibited by addition of CEO alone and in combination with CNPs in zein films, while CNPs-loaded zein film had no significant effect on the growth of microorganisms. Thus, it can be concluded that the reinforced zein based composites could be suggested as potential degradable film-forming materials for food packaging applications.

The effect of polyethylene glycol on the characteristics of kenaf cellulose/low-density polyethylene biocomposites.

Toward the development of biocomposites for packaging applications, the possibility of using kenaf cellulose (KC) was investigated in the production of low-density polyethylene (LDPE)/KC/polyethylene glycol (PEG) biocomposites. First, cellulose was extracted from the cell walls of kenaf-bast fibers. Then, different weights of LDPE, KC, and PEG were blended, and the effects of varying the concentrations of KC and PEG on the synthesis process were evaluated, and the resulting composites were characterized with respect to their mechanical, thermal, biodegradability and water-absorption properties. A scanning electron microscope (SEM) was also used to observe the surface morphology of the samples before and after biodegradation tests. The results showed that the mechanical properties of the biocomposites decreased slightly as the KC content was increased from 0 to 50wt% in the biocomposite formulation; however, there was a good homogeneity between samples with added PEG. The addition of KC improved the thermal resistance of these biocomposites; PEG also had positive role in the thermal behavior of the composites. Based on a soil-burial test, the biodegradability of the composites showed a clear trend of increase degradation with increasing KC content in the formulation. While water-absorption values for the composites were higher than that of pure LDPE polymer, the addition of PEG to the formulation reduced the water absorption of the composites.