This review describes the most common methods for recovery of chitin from marine organisms. In depth, both enzymatic and chemical treatments for the step of deproteinization are compared, as well as different conditions for demineralization. The conditions of chitosan preparation are also discussed, since they significantly impact the synthesis of chitosan with varying degree of acetylation (DA) and molecular weight (MW). In addition, the main characterization techniques applied for chitin and chitosan are recalled, pointing out the role of their solubility in relation with the chemical structure (mainly the acetyl group distribution along the backbone). Biological activities are also presented, such as: antibacterial, antifungal, antitumor and antioxidant. Interestingly, the relationship between chemical structure and biological activity is demonstrated for chitosan molecules with different DA and MW and homogeneous distribution of acetyl groups for the first time. In the end, several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability.

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Chitin and Chitosan Preparation from Marine Sources. Structure, Properties and Applications

Natural-based plasticizers and biopolymer films: A review

Microencapsulation involves the incorporation of food ingredients, enzymes, cells, or other materials in small capsules. Microcapsules offer food processors a means with which to protect sensitive food components, ensure against nutritional loss, utilize otherwise sensitive ingredients, incorporate unusual or time-release mechanisms into the formulation, mask or preserve flavors and aromas, and transform liquids into easily handled solid ingredients. Various techniques are employed to form microcapsules, including spray drying, spray chilling or spray cooling, extrusion coating, fluidized-bed coating, liposome entrapment, coacervation, inclusion complexation, centrifugal extrusion, and rotational suspension separation. Recent developments in each of these techniques are discussed in this review. Controlled release of food ingredients at the right place and the right time is a key functionality that can be provided by microencapsulation. A timely and targeted release improves the effectiveness of ...

Recent Developments in Microencapsulation of Food Ingredients

Food wastes are today considered as a cheap source of valuable components since the existent technologies allow the recovery of target compounds and their recycling inside food chain as functional additives in different products. The goal of the current article is to classify food waste sources and high-added value ingredients prior to exploring the recovery stages, conventional and emerging technologies applied from the raw material to the final or encapsulated product. Safety and cost aspects were discussed, too, while a survey of patented methodologies leading to real products was listed, with a final purpose of discussing the prevalent problems that restrict the commercialization of similar procedures.

Recovery of high added-value components from food wastes: Conventional, emerging technologies and commercialized applications

Research and development of bio-nanocomposite materials for food applications such as packaging and other food contact surfaces is expected to grow in the next decade with the advent of new polymeric materials and composites with inorganic nano-particles. This article reviews different types of new bio-based materials, such as edible and biodegradable nanocomposite films, their commercial applications as packaging materials, regulations and future trends. Special emphasis is given to the advantages of nanotechnology application in order to improve the mechanical and oxidation stability, the barrier properties, and eventually the biodegradability of conventional polymeric matrices.

Potential perspectives of bio-nanocomposites for food packaging applications

Biodegradable blend films from rice starch–chitosan were developed by casting film-solution on leveled trays. The influence of the ratio of starch and chitosan (2:1, 1.5:1, 1:1, and 0.5:1) on the mechanical properties, water barrier properties, and miscibility of biodegradable blend films was investigated. The biodegradable blend film from rice starch–chitosan showed an increase in tensile strength (TS), water vapor permeability (WVP), lighter color and yellowness and a decreasing elongation at the break (E), and film solubility (FS) after incorporation of chitosan. The introduction of chitosan increased the crystalline peak structure of starch film; however, too high chitosan concentration yielded phase separation between starch and chitosan. The amino group band of the chitosan molecule in the FTIR spectrum shifted from 1541.15 cm−1 in the chitosan film to 1621.96 cm−1 in the biodegradable blend films. These results pointed out that there was a molecular miscibility between these two components. The properties of rice starch–chitosan biodegradable blend film and selected biopolymer and synthetic polymer films were compared; the results demonstrated that rice starch–chitosan biodegradable blend film had mechanical properties similar to the other chitosan films. However, the water vapor permeability of rice starch–chitosan biodegradable blend film was characterized by relatively lower water vapor permeability than chitosan films but higher than polyolefin.

Preparation and properties of rice starch–chitosan blend biodegradable film

Na-alginate- and κ-carrageenan-based antimicrobial films were prepared, to examine their antimicrobial effect and mechanical properties. Antimicrobial agents: lysozyme, nisin, grape fruit seed extract (GFSE) and ethylenediaminetetraacetic acid (EDTA) were incorporated into films, both alone and in combination. Na-alginate-based films exhibited larger inhibitory zones compared to κ-carrageenan-based films even within similar combinations and levels of antimicrobial agents. GFSE-EDTA in both Na-alginate- and κ-carrageenan-based films showed inhibitory effect against all indicator microorganisms. Tensile strength (TS) values were weaker and elongations (E) before breakage less frequent for films with antimicrobial compounds compared to that of films without the antimicrobial compounds.

Antimicrobial Films Based on Na-alginate and κ-carrageenan

The effectiveness in moisture retention and reduction of fat uptake of different edible coatings on a fat-free starchy product was determined. Mashed potato balls of 47 mm diameter were used as model food system. Samples were coated with corn zein (CZ), hydroxypropyl methyl cellulose (HPMC) or methyl cellulose (MC) film-forming solutions. Uncoated samples were used as control. Compared to the control, a reduction of 14.9%, 21.9% and 31.1% in moisture loss from the product was observed for samples coated with CZ, HPMC and MC films, respectively. Similarly, a reduction of 59.0%, 61.4% and 83.6% in fat uptake by the product was observed for samples coated with CZ, HPMC and MC films, respectively. Based on the overall performance in reducing moisture loss and fat uptake, MC exhibited the most significant barrier properties.

Edible coatings for deep-fat frying of starchy products

The efficiency of decorticating cowpeas was improved by hydrating to 25%, then drying to ˜10% moisture. Effects of drying temperature (50°, 70°, 90°, 110°, and 130°C) on functional and nutritional properties of cowpea meal were assessed. Extraction rate (yield) was unaffected by heating. Average particle size and water absorption of meal were greatest for intermediate temperatures. Starch was not gelatinized at any temperature. Reduction in protein solubility, which occurred at temperature 90°C., was associated with changes in gel electrophoresis patterns. Protein solubility was negatively correlated with previously reported values for specific gravity and apparent viscosity of cowpea pastes. Increases in drying temperature reduced thiamin content and increased browning of the meal.

Manjeet S. Chinnan

Papers

Preparation and properties of rice starch–chitosan blend biodegradable film

Antimicrobial Films Based on Na-alginate and κ-carrageenan

Edible coatings for deep-fat frying of starchy products

Effects of Pretreatment on Functional and Nutritional Properties of Cowpea Meal

Utilization of cowpeas for human food