Hydrolytic Stability of l-(+)-Ascorbic Acid in Low Methoxyl Pectin Films with Potential Antioxidant Activity at Food Interfaces

Sunflower (Helianthus annuus L.) Seed Hull Waste: Composition, Antioxidant Activity, and Filler Performance in Pectin-Based Film Composites

Helianthus annuus L. seed hull is an abundant waste of the edible oil industry. To envisage potential applications of this waste, here, we aimed to analyze the chemical composition of milled sunflower hulls (SP), constituted mainly by 210 μm (51.4%) and 420 μm (27.6%) average mesh particle sizes. SP contained almost 30% of cellulose, 26.4% of lignin, 38.5% of neutral sugars, mainly hemicelluloses, and only 1.3% of proteins. The important lignin content and low pectin content (4.0% of uronic acids) present in SP were both ascribed to its low hydrophilic behavior and hydration capacity. Phenolic compounds were mostly proanthocyanidins (168 mg/100 g SP), with lower amounts of extractable (31.4 mg/100 g SP) phenolics (O-caffeoylquinic acid), all of them associated with the DPPH radical scavenging capacity (95 mg ascorbic acid equiv./100 g) and ferric reducing power (FRAP: 152 mg ascorbic acid equiv./100 g) shown by SP. Esterified ferulic acid (52.9 mg/100 g SP) was also found, mostly as monomers and trimers. SP of 53 μm particle size was then assayed as a filler (0, 5, 8, and 12% concentrations) in calcium low methoxyl pectin-based films, which showed antioxidant capacity (DPPH and FRAP assays) in an SP-concentration-dependent manner. SP showed homogeneous dispersion in composite films equilibrated at 57.7% relative humidity. Water content decreased while film thickness increased with SP concentration. When loaded at a 12% level, the presence of 53-μm SP decreased the water vapor permeability and increased the normal stress at film fracture. Sunflower hulls can then be applied to the development of active materials like 12% SP film, which can be proposed as a food slice antioxidant separator to be investigated in a future work.

Application of Encapsulation Technology in Edible Films: Carrier of Bioactive Compounds

Nutraceuticals, functional foods, immunity boosters, microcapsules, nanoemulsions, edible packaging, and safe food are the new progressive terms, adopted to describe the food industry. Also, the rising awareness among the consumers regarding these has created an opportunity for the food manufacturers and scientists worldwide to use food as a delivery vehicle. Packaging performs a very imminent role in the food supply chain as well as it is a consequential part of the process of food manufacturing. Edible packaging is a swiftly emerging art of science in which edible biopolymers like lipids, polysaccharides, proteins, resins, etc. and other consumable constituents extracted from various non-conventional sources like microorganisms are used alone or imbibed together. These edible packaging are indispensable and are meant to be consumed with the food. This shift in paradigm from traditional food packaging to edible, environment friendly, delivery vehicles for bioactive compounds have opened new avenues for the packaging industry. Bioactive compounds imbibed in food systems are gradually degenerated, or may change their properties due to internal or external factors like oxidation reactions, or they may react with each other thus reducing their bioavailability and ultimately may result in unacceptable color or flavor. A combination of novel edible food-packaging material and innovative technologies can serve as an excellent medium to control the bioavailability of these compounds in food matrices. One promising technology for overcoming the aforesaid problems is encapsulation. It can be used as a method for entrapment of desirable flavors, probiotics, or other additives in order to apprehend the impediments of the conventional edible packaging. This review explains the concept of encapsulation by exploring various encapsulating materials and their potential role in augmenting the performance of edible coatings/films. The techniques, characteristics, applications, scope, and thrust areas for research in encapsulation are discussed in detail with focus on development of sustainable edible packaging.

Fortification of edible films with bioactive agents: a review of their formation, properties, and application in food preservation

Biodegradable films constructed from food ingredients are being developed for food coating and packaging applications to create more sustainable and environmentally friendly alternatives to plastics and other synthetic film-forming materials. In particular, there is a focus on the creation of active packaging materials from natural ingredients, especially plant-based ones. The film matrix is typically constructed from film-forming food components, such as proteins, polysaccharides and lipids. These matrices can be fortified with active ingredients, such as antioxidants and antimicrobials, so as to enhance their functional properties. Edible active films must be carefully designed to have the required optical, mechanical, barrier, and preservative properties needed for commercial applications. This review focuses on the fabrication, properties, and functional performance of edible films constructed from natural active ingredients. It provides an overview of the type of active ingredients that can be used, how they interact with the film matrix, how they migrate through the films, and how they are released. It also discusses the potential application of these active films for food preservation. Finally, future trends are highlighted and areas where further research are required are discussed.

Investigation of the structural, physical properties, antioxidant, and antimicrobial activity of chitosan- nano-silicon aerogel composite edible films incorporated with okara powder

The chitosan/okra powder/nano-silicon aerogel composite films were prepared by casting method and their physicochemical properties and structural characterization were studied. The results showed that the composite film had good mechanical properties, barrier properties and optical properties. The composite film has strong flexibility. The surface glossiness of C/D/S1.5:1:0.1 film was 14.4Gu. As for the antibacterial activity, all the composite films had strong antibacterial activity against Gram-negative (E. coli) and Gram-positive (S. aureus), and the inhibition zone of C/D/S1.5:1:0.10 against E. coli reached 551.96 mm2, the inhibition zone for S. aureus was 350.29 mm2. The composite film had uniform, non-porous, continuous and dense surface characteristics. The structural characterization confirmed that there was good compatibility between chitosan, okara powder and nano-silicon aerogel. In summary, the composite films had excellent performance and structure, which promoted the research of functional packaging films.

Degradation of L-Ascorbic Acid in the Amorphous Solid State

Ascorbic acid degradation in amorphous solid dispersions was compared to its degradation in the crystalline state. Physical blends and lyophiles of ascorbic acid and polymers (pectins and polyvinylpyrrolidone [PVP]) were prepared initially at 50:50 (w/w), with further studies using the polymer that best inhibited ascorbic acid crystallization in the lyophiles in 14 vitamin : PVP ratios. Samples were stored in controlled environments (25 to 60 °C, 0% to 23% RH) for 1 mo and analyzed periodically to track the physical appearance, change in moisture content, physical state (powder x-ray diffraction and polarized light microscopy), and vitamin loss (high performance liquid chromatography) over time. The glass transition temperatures of select samples were determined using differential scanning calorimetry, and moisture sorption profiles were generated. Ascorbic acid in the amorphous form, even in the glassy amorphous state, was more labile than in the crystalline form in some formulations at the highest storage temperature. Lyophiles stored at 25 and 40 °C and those in which ascorbic acid had crystallized at 60 °C (≥70% ascorbic acid : PVP) had no significant difference in vitamin loss (P > 0.05) relative to physical blend controls, and the length of storage had little effect. At 60 °C, amorphous ascorbic acid lyophiles (≤60% ascorbic acid : PVP) lost significantly more vitamin (P < 0.05) relative to physical blend controls after 1 wk, and vitamin loss significantly increased over time. In these lyophiles, vitamin degradation also significantly increased (P < 0.05) at lower proportions of ascorbic acid, a scenario likely encountered in foods wherein vitamins are naturally present or added at low concentrations and production practices may promote amorphization of the vitamin.

PRACTICAL APPLICATION

Vitamin C is one of the most unstable vitamins in foods. This study documents that amorphous ascorbic acid is less stable than crystalline ascorbic acid in some environments (for example, higher temperatures within 1 wk), especially when the vitamin is present at low concentrations in a product. These findings increase the understanding of how material science properties influence the stability of vitamin C.

Pectin-based composite film: Effect of corn husk fiber concentration on their properties

Considering the polysaccharide composition and 32% of crystallinity of the water insoluble fiber extracted from corn husk (CHF) agricultural residue, its filler performance as water vapor permeability (WVP) and mechanical modifier in edible films based on commercial low methoxyl pectin (LMP) was evaluated (0, 1, 3, 5, 8% concentrations). The 53-μm-CHF carried phenolics and carotenes, and composites showed antioxidant capacity. Homogeneous films with a continuous LMP matrix were obtained. The 5%-CHF composite showed the highest surface contact angle (44°) and tensile strength, without change in elongation, while WVP was decreased in the 3-8% CHF-LMP-films. The latter was ascribed to the CHF-filler crystallinity whereas the improvement in mechanical performance and contact angle was attributed to a CHF-interconnected network formed at 5%-CHF critical concentration. Corn husk residue can be utilized as a source of fibers for material development. Composites with enhanced performance can be an antioxidant strategy at food interfaces.

Films and edible coatings containing antioxidants - a review

The incorporation of natural antioxidants into films and edible coatings can modify their structure, improving their functionality and applicability in foods, such as in fresh-cut fruits. This paper reviews the more recent literature on the incorporation of antioxidants from several sources into films and edible coatings, for application in fruits and vegetables. The use of synthetic antioxidants in foods has been avoided due to their possible toxic effects. Instead, a wide range of natural antioxidants (such as essential oils and plant extracts, as well as pure compounds, like ascorbic acid and α-tocopherol) have been incorporated into edible films and coatings to improve their bioactive properties. Films and coatings containing added antioxidants help to preserve or enhance the sensory properties of foods and add value to the food products by increasing their shelf life.

Hydrolytic and oxidative stability of L-(+)-ascorbic acid supported in pectin films: influence of the macromolecular structure and calcium presence

The hydrolytic and oxidative stability of L-(+)-ascorbic acid (AA) into plasticized pectin films were separately studied in view of preserving vitamin C activity and/or to achieve localized antioxidant activity at pharmaceutical and food interfaces. Films were made with each one of the enzymatically tailored pectins (50%, 70%, and 80% DM; Cameron et al. Carbohydr. Polym.2008, 71, 287-299) or commercial high methoxyl pectin (HMP; 72% DM). Since AA stability was dependent on water availability in the network, pectin nanostructure affected the AA kinetics. Higher AA retention and lower browning rates were achieved in HMP films, and calcium presence in them stabilized AA because of higher water immobilization. Air storage did not change AA decay and browning rates in HMP films, but they significantly increased in Ca-HMP films. It was concluded that the ability of the polymeric network to immobilize water seems to be the main factor to consider in order to succeed in retaining AA into film materials.