Bioactive packaging: turning foods into healthier foods through biomaterials

Examination of the technological properties of newly isolated strains of the genus Lactobacillus and possibilities for their application in the composition of starters

The ability of four Lactobacillus strains – Lactobacillus brevis LBRZ7 (isolated from fermented cabbage), Lactobacillus plantarum LBRZ12 (isolated from fermented cabbage), Lactobacillus fermentum LBRH9 (of human origin) and Lactobacillus casei ssp. rhamnosus LBRC11 (isolated from home-made cheese) – to grow in flour/water environment and to accumulate high concentrations of viable cells was examined. Two starters for sourdough were created for lab-scale production of wheat bread: a two-strain starter and a four-strain starter. Wheat bread with improved properties – greater loaf volume, enhanced flavour and softer and brighter crumb – was obtained from the 7% four-strain starter sourdough. The addition of sourdough in the production of wheat bread affected positively the technological and organoleptic characteristics of the final bread by inhibiting the growth of wild yeasts and mold and Bacillus spores without the addition of preservatives. The inclusion of 15% of the four-strain starter sourdough in the bread-making process led to enhanced safety and longer shelf life of the baked bread.

Improving the capacity of polypropylene to be used in antioxidant active films: incorporation of plasticizer and natural antioxidants

Two types of active antioxidant food packages with improved release properties, based on polypropylene (PP) as one of the most common polymers used in food-packaging applications, were developed. Incorporation of catechin and green tea as antioxidant provided PP with 6 times higher stabilization against thermal oxidation. Release of natural antioxidants (catechins, gallic acid, caffeine, and quercetin) into various food simulants from that nonpolar matrix were improved by blending poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) (PPG-PEG-PPG) as plasticizer into the polymer formulation. Increasing release levels between 10- and 40-fold into simulant A and between 6 and 20-fold into simulant D1 resulted from the incorporation of catechin and green tea as antioxidants and PPG-PEG-PPG as plasticizer into the film formulation. The efficiency of the antioxidants in the food simulants after the release process was also corroborated through antioxidant activity tests. Therefore, the developed PPG-PEG-PPG-modified polypropylene resulted in a potential system to be used in active packaging.

Nutraceutically inspired pectin-Mg(OH)₂ nanocomposites for bioactive packaging applications

This paper reports on the development of bioactive edible films based on pectin as a dietary matrix and magnesium hydroxide (Mg(OH)2) nanoplates as a reinforcing filler. Nanocomposites of high-methoxyl (HM) and low-methoxyl (LM) pectins were prepared using the casting method at concentrations of Mg(OH)2 ranging from 0.5 to 5 wt %. Atomic force microscopy and FTIR spectroscopy were employed to characterize the nanocomposite structure. The tensile properties and thermal stability of the nanocomposites were also examined to ascertain the effect of Mg(OH)2 inclusion and degree of methoxylation. The results provided evidence that the Mg(OH)2 nanoplates were uniformly dispersed and interacted strongly with the film matrix. The mechanical and thermal properties were significantly improved in the nanocomposite films compared to the control. Mg(OH)2 nanoplates were more effective in improving properties of LM pectin. Preliminary migration studies using arugula leaves confirmed that pectin-Mg(OH)2 nanocomposites can release magnesium hydroxide by contact, demonstrating their potential for magnesium supplementation in bioactive packaging.

Development of antimicrobial packaging materials with immobilized glucose oxidase and lysozyme

Packaging based on immobilization of antimicrobial enzymes provides a promising form of active packaging systems applicable in food processing. Glucose oxidase and lysozyme were immobilized by the Ugi reaction with cyclohexyl isocyanide and glutaraldehyde on polyamide and ionomer films partially hydrolysed by hydrochloric acid. The immobilization of the enzymes on the surface of films was confirmed by FT-IR spectroscopy and the films were characterized by the specific activity of the immobilized enzymes. The enzyme migration into model solutions and the effect of pH, temperature and storage time on the activity of immobilized enzyme were also evaluated. Immobilization of lysozyme onto polyamide and ionomer films resulted in the loss of enzyme activity. The polyamide and ionomer films with immobilized glucose oxidase inhibited the growth of bacteria Escherichia coli CNCTC 6859, Pseudomonas fluorescens CNCTC 5793, Lactobacillus helveticus CH-1, Listeria ivanovii CCM 5884 and Listeria innocua CCM 4030 on agar media.

COMPARISON OF NANOTECHNOLOGY ACCEPTANCE IN TURKEY AND SWITZERLAND

The aim of this paper is to replicate the study of Siegrist et al. [2007] and to present a comparison of nanotechnology acceptance in Turkey and Switzerland. The participants in our survey acknowledge the benefits of nanotechnology in achieving a preferred future (significance on the country's economy and on wealth creation, as well as quality of life) while reserving some sceptism on the institutions' responsibility in utilizing nanotechnology in the food domain.

The most beneficial application in our study is viewed as nanotechnology-used bread compared to food packaging of Swiss study. The most risky application is seen as the application for tomatoes, the most affect is observed again for the tomatoes and willingness to buy(WTB) choice is more for juice application than any other applications analyzed in this study. Perceived benefits and perceived risks are found to have influence on the WTB nanotechnology applications in the food domain. Results did not support any evidence suggesting that the nanoinside applications are perceived as less acceptable than nanooutside application as stated in the Swiss study. Affect evoked by the information existing in environment about the nanotechnology products have significant relation with benefits and risks of this emerging technology. The relation between affect and risk in our model is positive whereas it is negative in Siegrist et al. [2007]. The effect of social trust on affect is found to be insignificant in our study which was an assumption of Siegrist et al. [2007] and found to be significant in their research.

This paper attempts to help the managers to understand the youth and young adults' perception of nanotechnology in Turkey and to consider the importance of those perceptions for the realization of technological advances in improving their products and developing new ones.

The microbiological and immunomodulatory effects of spray-dried versus wet dietary supplementation of seaweed extract in the pig gastrointestinal tract

Seaweeds and seaweed extract (SWE) possess antimicrobial, anti-inflammatory, prebiotic, and growth-promoting properties. Extracts can be prepared in different ways including wet, spray-dried, and freeze-dried forms. The aim of this study was to determine if spray drying of laminarin and fucoidan derived from Laminaria digitata had an effect on the microbiological and cytokine profile of the gastrointestinal tract (GIT) compared to the wet SWE in newly weaned pigs. No differences in cytokine expression were observed between wet and spray dried SWE formulation in either the ileum or colon. Bifidobacteria counts were greater (P < 0.05) in the wet SWE formulation relative to both spray dried SWE and the basal diet in the ileum. In conclusion, neither of the SWE formulations had significant effects on the cytokine profile in the ileum or colon. However, a prebiotic effect observed in the ileum of piglets in response to the wet SWE formulation was lost following spray drying of the SWE.

Preparation, characterization and efficacy evaluation of synthetic biocompatible polymers linking natural antioxidants

The purpose of this work was the synthesis, characterization and efficacy evaluation of new biocompatible antioxidant polymers linking trans-ferulic acid or α-lipoic acid. In particular, ferulic or lipoic acid were introduced in the preformed polymeric backbone. The new antioxidant biopolymers were characterized by Fourier transform infrared spectroscopy and gel permeation chromatography. The degree of functionalization (moles of antioxidant per gram of polymer) was determined by the Gaur-Gupta method for free amino group determination and by the Folin method for the phenolic groups. Their ability to inhibit lipid peroxidation were estimated in rat liver microsomal membranes induced in vitro by tert-BOOH (tert-butyl hydroperoxide), as a source of free radicals. The DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging effect was also evaluated. The obtained systems, with different solubility, showed strong antioxidant and antiradical activities, suggesting potential use as packaging materials for foods, cosmetics, pharmaceuticals and personal care products. Moreover, the cytotoxicity of the synthesized polymers was also evaluated on Caco-2 cell cultures in order to verify their biocompatibility when exposed to an absorptive epithelial cell line.

Effect of PPG-PEG-PPG on the tocopherol-controlled release from films intended for food-packaging applications

The feasibility of novel controlled release systems for the delivery of active substances from films intended for food packaging was investigated. Because polyolefins are used highly for food-packaging applications, the reported high retention degree of antioxidants has limited their use for active packaging. Thus, in this study, PP films modified with different chain extenders have been developed to favor and control the release rates of the low molecular weight antioxidant tocopherol. The use of different chain extenders as polymer modifiers (PE-PEG M(w), 575; and PPG-PEG-PPG M(w), 2000) has caused significant changes in tocopherol-specific release properties. High-performance liquid chromatography coupled to PDA-FL and PDA-MS was used to test tocopherol and chain extender migration, respectively. The release of tocopherol from the prepared films with two chain extenders into two food simulants was studied. Different temperatures and storage times were also tested. Varying the structural features of the films with the incorporation of different levels of PPG-PEG-PPG, the release of tocopherol (food-packaging additive) into different ethanolic simulants could be clearly controlled. The effect of the temperature and storage time on the release of the antioxidant has been outstanding as their values increased. The migration of the chain extender, also tested, was well below the limits set by European legislation.

Revisão: alimentos frescos minimamente processados embalados em atmosfera modificada

Os alimentos frescos, minimamente processados e embalados sob atmosfera modificada atraem os consumidores que procuram produtos frescos e saudáveis, e que, ao mesmo tempo, são fáceis de transportar e preparar. A atmosfera no interior das embalagens consiste numa mistura de gases que está otimizada para cada alimento, de modo a preservar as suas qualidades durante mais tempo. A manutenção da temperatura de refrigeração durante o processamento, o armazenamento, a distribuição e a comercialização é essencial, por causa da natureza perecível dos produtos frescos minimamente processados. Este trabalho discute o estado de arte dos alimentos frescos minimamente processados (frutas, vegetais, carnes e pescados) embalados em atmosfera modificada, com uma descrição pormenorizada dos últimos desenvolvimentos nesse campo.

Active food packaging evolution: transformation from micro- to nanotechnology

Predicting which attributes consumers are willing to pay extra for has become straightforward in recent years. The demands for the prime necessity of food of natural quality, elevated safety, minimally processed, ready-to-eat, and longer shelf-life have turned out to be matters of paramount importance. The increased awareness of environmental conservation and the escalating rate of foodborne illnesses have driven the food industry to implement a more innovative solution, i.e. bioactive packaging. Owing to nanotechnology application in eco-favorable coatings and encapsulation systems, the probabilities of enhancing food quality, safety, stability, and efficiency have been augmented. In this review article, the collective results highlight the food nanotechnology potentials with special focus on its application in active packaging, novel nano- and microencapsulation techniques, regulatory issues, and socio-ethical scepticism between nano-technophiles and nano-technophobes. No one has yet indicated the comparison of data concerning food nano- versus micro-technology; therefore noteworthy results of recent investigations are interpreted in the context of bioactive packaging. The next technological revolution in the domain of food science and nutrition would be the 3-BIOS concept enabling a controlled release of active agents through bioactive, biodegradable, and bionanocomposite combined strategy.

Quality and safety aspects of meat products as affected by various physical manipulations of packaging materials

This article explores the effects of physically manipulated packaging materials on the quality and safety of meat products. Recently, innovative measures for improving quality and extending the shelf-life of packaged meat products have been developed, utilizing technologies including barrier film, active packaging, nanotechnology, microperforation, irradiation, plasma and far-infrared ray (FIR) treatments. Despite these developments, each technology has peculiar drawbacks which will need to be addressed by meat scientists in the future. To develop successful meat packaging systems, key product characteristics affecting stability, environmental conditions during storage until consumption, and consumers' packaging expectations must all be taken into consideration. Furthermore, the safety issues related to packaging materials must also be taken into account when processing, packaging and storing meat products.

Encapsulation of living bifidobacteria in ultrathin PVOH electrospun fibers

This study shows the application of the electrospinning technique as a viable method for the encapsulation and stabilization of bifidobacterial strains. Poly(vinyl alcohol) (PVOH) was used as the encapsulating material because it is generally recognized as safe (GRAS), has a high oxygen barrier when dry, and is water soluble, hence allowing easy recovery of the bacteria for viability testing. A coaxial setup was used for encapsulation, and the so-obtained electrospun fibers had a mean diameter of ca. 150 nm. Incorporation of B. animalis Bb12 led to a decrease in melting point and crystallinity of the PVOH fibers and to an increase in the polymer glass transition temperature. The viability tests, carried out at three different temperatures (room temperature and 4 and -20 degrees C) showed that B. animalis Bb12 encapsulated within the electrospun PVOH fibers remained viable for 40 days at room temperature and for 130 days at refrigeration temperature, whereas a significant viability decrease was observed in both cases when bacteria were not encapsulated (p = 0.015 and p = 0.002, respectively).