Physical and antioxidant properties of chitosan and methylcellulose based films containing resveratrol

New trends in edible films focus on the improvement of their functionality through the incorporation of active compounds, such as antimicrobial or antioxidant agents. Resveratrol is a natural antioxidant found in a variety of plant species, such as grapes, and could be used for minimizing or preventing lipid oxidation in food products, retarding the formation of oxidation products, maintaining nutritional quality and prolonging the food shelf life. The aim of this work was to develop and characterize two different polymeric composite films (made with chitosan (CH) and methylcellulose (MC)) containing different amounts of resveratrol. This compound could be incorporated efficiently into both films, but provoke structural changes in the matrices, which became less stretchable (65–70% reduction of deformation at break at the greatest resveratrol content) and resistant to fracture (26 and 54% reduction of tensile at break for MC and CH, respectively, at the greatest resveratrol content) more opaque (significant reduction of the internal transmittance) and less glossy (about 60–65% reduction of gloss at the greatest resveratrol content). Film barrier properties were hardly improved by the presence of resveratrol; water vapour and oxygen permeability tend to slightly decrease when resveratrol was incorporated into both polymers. Composite films showed antioxidant activity, which was proportional to the resveratrol concentration in the film. None of the films showed antimicrobial activity against Penicillium italicum and Botrytis cinerea. Thus, these films could be applied to food products which are sensitive to oxidative processes to prolong their shelf life.     

Miniaturization of cellulose fibers and effect of addition on the mechanical and barrier properties of hydroxypropyl methylcellulose films

Cellulose fibers were miniaturized by microfluidics technology to decrease their size and incorporated in hydroxypropyl methylcellulose (HPMC) films to study the effect of addition of such fibers on the mechanical and barrier properties of HPMC films suitable for application in food packaging. The particle size of fibers and the mechanical properties, water vapor and oxygen permeabilities, total pore volume, and light and electron microscopy micrographs of films were analyzed. Incorporation of cellulose fibers in the films improved their mechanical and barrier properties significantly. This study is the first to investigate the use of microfluidics technology for the purpose of decreasing the size of cellulose fibers and the addition of reduced size microfibers to improve physical properties of HPMC films.     

PHYSICAL AND SENSORY PROPERTIES OF LEAN GROUND BEEF PATTIES CONTAINING METHYLCELLULOSE AND HYDROXYPROPYLMETHYLCELLULOSE1

Broiled, lean ground beef patties containing no additives, two levels of methylcellulose (MC, 0.5 or 1.0%) and two levels of hydroxypropylmethylcellulose (HPMC, 0.5 or 1.0%) were evaluated for raw and cooked composition, cooking losses, sensory attributes and Instron compression measurements. MC or HPMC addition did not significantly affect the fat, moisture or protein content of the raw and cooked patties. Patties containing HPMC received greater tenderness, juiciness and off-flavor sensory scores when compared with patties containing MC or no additive. MC or HPMC addition increased patty gumminess sensory scores and decreased Instron compression values. Sensory cooked meat flavor decreased with gum addition.     

Development of cellulose-based bactericidal nanocomposites containing silver nanoparticles and their use as active food packaging

The use of nanomaterials, including metallic as active fillers in polymeric nanocomposites for food packaging has been extensively investigated. Silver nanoparticles (AgNPs), in particular, have been exploited for technological applications as bactericidal agents. In this paper, AgNPs were incorporated into a hydroxypropyl methylcellulose (HPMC) matrix for applications as food packaging materials. The average sizes of the silver nanoparticles were 41 nm and 100 nm, respectively. Mechanical analyses and water vapor barrier properties of the HPMC/AgNPs nanocomposites were analysed. The best results were observed for films containing smaller (41 nm) AgNPs. The antibacterial properties of HPMC/AgNPs thin films were evaluated based on the diameter of inhibition zone in a disk diffusion test against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The disk diffusion studies revealed a greater bactericidal effectiveness for nanocomposites films containing 41 nm Ag nanoparticles.     

High methoxyl pectin–methyl cellulose films with antioxidant activity at a functional food interface

The effect of using increasing proportions of methylcellulose (MC) for the development of glycerol plasticized films based on high methoxyl pectin (HMP) (30:70, 50:50 and 70:30 w/w HMP:MC) and carrying l-(+)-ascorbic acid (AA) was studied with the purpose of achieving higher stability of AA and localized antioxidant activity at food interfaces. MC and 30:70 HMP:MC systems could not be casted. The shelf-life of the other AA-active films was assessed by storage at 25 °C, constant relative humidity (RH: 33.3%, 57.7% and 75.2%) and vacuum conditions. The rate constant for AA hydrolysis increased with the RH and, hence, with water mobility. Browning and AA degradation rates were directly related. When stored at 75.2% RH, both decreased as MC proportion increased. Compared to HMP film, the highest proportion of MC (50:50 HMP:MC) showed the highest AA stabilization under vacuum and greater performance under air atmosphere. They also developed localized antioxidant activity preserving the tocopherol content of walnut oil.     

Effect of hydroxypropyl methylcellulose on the textural and whipping properties of whipped cream

In this work, hydroxypropyl methylcellulose (HPMC) was added into whipped cream for improving its textural and whipping properties. By determination of the particle size distribution, a single peak for the emulsion after homogenization and two distinguishable peaks for the emulsion after whipping for 5 min were observed. With the increase of HPMC level, the average particle size (d_3,2) decreased for the emulsion after homogenization and increased for the emulsion after whipping for 5 min. Both whipping time and HPMC level showed positive effects on the partial coalescence of fat globules. The partial coalescence of whipped cream with 0.125% HPMC after whipping for 5 min reached 56.25%, significantly (P < 0.05) higher than that (4.77%) without whipping treatment. Surface protein concentration was measured to evaluate the change of protein content at the droplet interface. The results indicated that the increase of HPMC level could decrease the surface protein concentration slightly. The overrun of whipped cream slightly increased when the HPMC level increased in the range of 0.025–0.125%. Firmness, cohesiveness, consistency and viscosity of whipped cream were analysed in this work. HPMC showed a positive dose-dependent effect on all these textural properties.     

Nutritional characterization of tomato fiber as a useful ingredient for food industry

Tomato by-product consists of peels and seeds, presenting peel high fiber content. In this work, “tomato fiber” (TF) samples, obtained from tomato peels (after tomato processing) by a patented process, were characterized in terms of fiber and macronutrients (proteins, ash, total available carbohydrates and soluble sugars). From our results, TF is mainly composed by carbohydrates, with an average value of 80% of total dietary fiber (much higher than other vegetable by-products), being insoluble fiber the major component. The results obtained in this study reveal the high interest of TF as a food ingredient to be used as a valuable ingredient of new functional foods, enhancing insoluble fiber intake in the population.Industrial RelevanceThe use of tomato by-product reduces costs and justifies new investments in equipment, providing a correct solution for the pollution problem connected with tomato processing. The results obtained in this study reveal the high interest of TF as a food ingredient to be used as a valuable ingredient of new functional foods, enhancing insoluble fiber intake in the population. According to the Regulation 1924/2006, the product TF characterized in this study can be considered under the denomination of “Source of Fiber” (more than 3 g/100 g), and for that reason food products containing the above mentioned fiber in quantities equal or superior to 3.9%, could also include the same declaration of nutritional properties in their labeling.     

Performance of hydroxypropyl methylcellulose (HPMC)-lipid edible coatings with antifungal food additives during cold storage of ‘Clemenules’ mandarins

The performance of edible composite coatings containing hydroxypropyl methylcellulose (HPMC), hydrophobic components (beeswax and shellac), and food preservatives as antifungal ingredients was evaluated on ‘Clemenules’ clementine mandarins. Tested preservatives included potassium sorbate (PS), sodium benzoate (SB), sodium propionate (SP), and their mixtures. Intact fruit or fruit artificially inoculated with Penicillium digitatum or Penicillium italicum, the causal agents of citrus postharvest green (GM) and blue (BM) molds, respectively, were coated and stored up to 30 d at 5 °C plus 7 d at 20 °C of shelf-life. During cold storage, all HPMC-lipid coatings containing food additives significantly reduced the development of both GM and BM, although the performance was better against GM. When coated fruit were transferred to 20 °C, all coatings lost effectiveness. SB + PS-based coating was the most effective to reduce disease severity. All the coatings effectively reduced weight loss and maintained rind firmness of coated ‘Clemenules’ mandarins. The coatings did not adversely affect the ethanol content of the juice, sensory flavor, and fruit appearance. Although the internal gas concentration of coated fruit was modified, the coatings did not induce off-flavor.     

Plasticized methylcellulose coating for reducing oil uptake in potato chips

BACKGROUND: As a result of consumers' health concerns and the trend towards healthier and low‐fat food products, research has been undertaken to reduce the amount of fat absorbed in fried foods. This work focused on studying the efficacy of sorbitol and glycerol as plasticizers of methylcellulose coatings used to reduce oil uptake during the frying process of potato chips RESULTS: Changes in color, mechanical properties, water activity and lipid oxidation during storage were monitored. Also, an explanation regarding the different performances between both methylcellulose coatings with and without plasticizer was attained and techniques from the field of packaging films such as dynamic mechanical analyzer (DMA) and Fourier transform infrared spectroscopy were applied to analyze the behavior of coatings submitted to the frying operation. The application of a methylcellulose coating was an adequate choice to reduce oil absorption in fried potato chips. The most effective formulation was 10 g L^?1 methylcellulose with the addition of 7.5 g L^?1 sorbitol. With the incorporation of this formulation, oil absorption was reduced by 30%. Neither the sorbitol concentration nor the presence of the MC coating affected the puncture maximum force and color parameters L and a*. The results of the sensory analysis indicated that the panelists could not distinguish between the coated and uncoated potato chips. CONCLUSION: Methylcellulose‐based coating plasticized with sorbitol could be an alternative for obtaining healthier potato chips. Copyright © 2011 Society of Chemical Industry     

Influence of methylcellulose on attributes of β-carotene fortified starch-based filled hydrogels: Optical,rheological, structural,digestibility, and bioaccessibility properties

There is considerable interest in controlling the gastrointestinal fate of nutraceuticals to improve their efficacy. In this study, the influence of methylcellulose (an indigestible polysaccharide) on lipid digestion and β-carotene bioaccessibility was determined. The carotenoids were encapsulated within lipid droplets that were then loaded into rice starch hydrogels containing different methylcellulose levels. Incorporation of 0 to 0.2% of methylcellulose had little impact on the dynamic shear rheology of the starch hydrogels, which may be important for formulating functional foods with desirable textural attributes. The microstructure, lipid digestion, and β-carotene bioaccessibility of the filled hydrogels were measured as the samples were passed through simulated oral, gastric, and small intestinal phases. The lipid digestion rate and carotenoid bioaccessibility decreased with increasing methylcellulose. This effect was attributed to the ability of the methylcellulose to inhibit molecular diffusion, promote droplet flocculation, or bind gastrointestinal components thereby inhibiting triacylglycerol hydrolysis at the lipid droplet surfaces. This information may be useful for rationally designing functional foods with improved nutritional benefits.     

Formation and characterization of shellac-hydroxypropyl methylcellulose composite films

Shellac-hydroxypropyl methylcellulose composite films (Sh-HPMC-CFs) were produced and the effects of emulsifier and shellac concentration on the Sh-HPMC-CFs were investigated. Two emulsifiers, stearic acid (SA) and lauric acid (LA), with three ratios of shellac to emulsifier (100:1, 20:1, and 10:1) were tested to select the best ratio of shellac to emulsifier before testing the effect of shellac concentration. When compared to pure HPMC film, the WVP was decreased by 6 and 11% in the Sh-HPMC-CFs containing shellac to LA (ShLA) ratios of 100:1 and 20:1, respectively. However, all the ShSA-HPMC-CFs had higher WVP than the pure HPMC film. In relation to mechanical properties, the ShLA(20:1)-HPMC-CF had the lowest reduction in TS when compared to a pure HPMC film. Therefore, ShLA(20:1) was selected for further characterization. Surface morphology, cross sectional image, thermal stability, WVP, and mechanical properties of the Sh-HPMC-CFs were also measured at varying shellac concentrations (0.1, 0.5, 1.0, and 1.5%). The 0.1 and 0.5% Sh-HPMC-CFs had good distribution of shellac in the film structure while the 1.0 and 1.5% Sh-HPMC-CFs exhibited some agglomeration of shellac. The 0.1 and 0.5% Sh-HPMC-CFs had better moisture barrier than the pure HPMC film. All Sh-HPMC-CFs had better thermal stability than the pure HPMC film and its thermal stability increased as shellac concentration increased.     

谷物膳食纤维制备及应用研究综述

综述了谷物膳食纤维的制备、改性、检测方法以及在食品工业中的应用等方面的研究进展.尽管近几十年来谷物膳食纤维的研究取得了很大进步,但对其定义、检测、改性方法、生理功能的体内验证及其作用机制等基础研究以及其工业应用技术还有待进一步深入研究和探索.     

Analysis of diglycolic acid in food packaging,over the counter products,direct additive carboxymethyl cellulose,and retail foods

ABSTRACT

Carboxymethyl cellulose (i.e. CMC or cellulose gum) is used as a direct additive for foods and drugs to change texture and act as a binder. CMC can also be a fluid absorbent used in food packaging and food contact materials. CMC and other carboxymethyl starches are synthesised by condensing glycolic acid with monochloroacetic acid. Diglycolic acid (DGA) is a byproduct produced by this condensation which cannot be completely removed. Currently, there are no analytical methods to accurately detect and quantify DGA in foods and food packaging materials. A method using a methanol/water extraction coupled with weak anion exchange solid phase extraction cleanup for more complex matrices was developed. A novel LC-MS/MS method was used to determine the DGA concentration in food contact materials, food grade direct additive CMC, and foods containing CMC. This paper will discuss the development of a new method for the preparation and cleanup of various food matrices and LC-MS/MS analysis for the presence of DGA.     

高直链玉米淀粉/羟丙基甲基纤维素可食性膜的制备及性能研究

以高直链玉米淀粉(HACS)和羟丙基甲基纤维素(HPMC)为主要成膜基材,采用溶液流延法制备了HACS/HPMC可食性膜。研究了不同配比的HACS与HPMC对可食性膜的结晶性能、力学性能、亲水性能和水蒸气阻隔性能等的影响。结果表明,随着HPMC比例的增大,HACS与HPMC之间的氢键作用减弱,复合膜的水溶性增大,连续相由HACS转变为HPMC,但HACS与HPMC的相容性变差。HPMC可有效降低可食性膜的结晶程度并抑制其在储藏过程中的老化。在复合膜中,当HACS与HPMC比例为8∶2时,可食性膜具有最大抗拉强度(7.5 MPa)、断裂伸长率(14.7%)、水接触角(84.33°)和最低水蒸气透过系数(2.17×10~(-10 )g·m·m~(-2)·s~(-1)·Pa~(-1))。纯HACS膜和纯HPMC膜的透光性能均优于HACS/HPMC复合膜。     

Studies on use of Enteromorpha in snack food

Seaweeds, also known as sea vegetables, are of nutritional interest, as they are rich in vitamins, minerals and dietary fiber. Enteromorpha compressa (Linnaeus), green seaweed (chlorophyta), which is a rich source of iron and dietary fibre was used as an ingredient in the preparation of Pakoda, a common traditional snack food in India. Pakoda samples showed increases in ash, protein and total dietary fibre contents with increase in Enteromorpha level, accompanied by a nearly fivefold increase in iron content (26.4–126 mg/100 g) and fourfold increase in calcium content (30.1–124 mg/100 g). Bioavailability of iron in Enteromorpha, and Pakoda containing 7.5% of Enteromorpha, did not show any difference (55–56%) at pH 7.5 (intestinal condition). But, at pH 1.35 (gastric condition) the bioavailability of iron in Pakoda containing Enteromorpha was found to be slightly higher (27.1%) than that in Enteromorpha. Reducing power (155–222 μg/g) increased as the Enteromorpha level increased from 0% to 15%. But the addition of Enteromorpha was found to decrease free radical-scavenging activity and the total phenol content. Pakoda containing up to 7.5% of Enteromorpha was found to have a sensory quality comparable with that of Pakoda without Enteromorpha.     

Effects of methylcellulose,xanthan gum and carboxymethylcellulose on thermal properties of batter systems formulated with different flour combinations

The functionalities of hydrocolloid–flour mixtures in terms of the thermal properties of their resulting batter systems were investigated, and the effects of different thermal processes such as cooking–freezing–thawing (CFT) and freezing–cooking (FC) on thermal properties of the various batter systems were determined in this study. Differential scanning calorimetry (DSC) was used to determine thermal property parameters including gelatinization temperature (T_G), total enthalpies of gelatinization (ΔH_G), glass transition temperature (T_g), melting peak temperature (T_m), and total melting enthalpies (ΔH_m). The different thermal processes did not significantly affect either T_G or ΔH_G of batter systems, but they influenced the glass transition behavior and the ΔH_m of batter systems. The thermal processes also showed different effects on the batter systems containing different hydrocolloids such as methylcellulose (MC), carboxymethylcellulose (CMC), and xanthan gum (XG). The hydrocolloids shifted T_G upwards, depressed T_g, and increased T_m of batters. The effect of these hydrocolloids on glass transition temperature was more pronounced in raw samples (FC process) than in cooked samples and increased with increasing levels of CMC and MC used in the formulations. Batters with MC showed increased ΔH_m for all the thermal processes. CMC only showed significant effect on ΔH_m for cooked samples (CFT process). MC and CMC showed more pronounced effects on T_g for raw uncooked rice- and corn flour-based batters than on raw uncooked wheat flour-based batters. However, this special effect was not obvious in the batters containing 0.2% XG.     

Effect of hydroxypropyl methylcellulose and lipid on mechanical properties and water vapor permeability of coated paper

Biopolymers have the potential to serve as coating materials for paper to improve its performance properties. The objectives of this study were to determine the effect of hydroxypropyl methylcellulose (HPMC), glycerol (Gly) and beeswax (BW) coatings on the physical properties and water vapor permeability (WVP) of coated papers. It was found that HPMC coated paper showed significant differences on physical properties, compared with uncoated (p ? 0.05). Folding endurance of HPMC-based coated papers greatly increased which indicated improved durability of coated paper. Moreover, HPMC-based coated papers increased in stretch and decreased in tensile index. HPMC-based coatings reduced WVP and further reduction was obtained when beeswax was incorporated in the HPMC-lipid composite coated paper. Paper coated with hydrocolloid and lipid can be used to produce packages with the potential to be used to maintain agricultural produce quality for the food industry, and may have other applications (i.e., medical packaging).     

Wheat aleurone: separation, composition, health aspects, and potential food use

Over the last three decades substantial attention has been given to the role of dietary fiber in health and disease, in particular diabetes, cardiovascular disease, intestinal health, and some types of cancer. As a result the food industry started to add back fiber to refined foods and develop fiber rich foods. Scientists suggested that whole grain foods are superior to foods enriched with fibers obtained/synthesized using enzyme treatment, and thermal or chemical processing because the content of bioactive components and micronutrients in whole grain is more abundant. This triggered interest in how to isolate the micronutrient rich aleurone fiber fraction from wheat. Aleurone is a single cell layer at the inner site of the bran. It contains most of the minerals, vitamins, phenolic antioxidants, and lignans of the wheat grain. Novel milling and dry-fractionation techniques have recently allowed for full-scale separation of aleurone cells from the other layers of wheat bran, yielding a fiber rich concentrate which potentially contains many of the "whole grain kernel bioactives," which recently have been used in a variety of studies. The present review highlights available data on aleurone isolation, composition, intestinal physiology, and its metabolism and potential health benefits as well as its use in food.     

Effects of methyl cellulose-based coating on physiochemical properties and chemical hazards of Chinese fried dough cake during storage

Coating has been used as a practical method to ensure the physiochemical properties and reduce the chemical hazard of fried foods. Methyl cellulose (MC) was used as a coating material to pretreat Chinese fried dough cake (CFDC) before frying. The results showed that the water content, hardness and L* value of the 1% MC coated sample were 31.67%, 848.54 g and 51.62, respectively, at the seventh day at 25 °C. Coating contents 1% MC could reduce the oil content, hardness, and extent of browning and improve the physiochemical properties of CFDC on 7 days of storage. Coating contents 1% MC also reduced the acid value, peroxide value, p-anisidine value, malondialdehyde content, 4-hydroxy-2-(E)-hexenal content, 4-hydroxy-2-(E)-nonenal content, acrylamide content and glycidyl ester content in CFDC on 7 days of storage. Our work contributes to the control of the oil content and chemical hazards for fried food during storage by applying an edible coating.     

Pasting characteristics of wheat flour-based batters containing cellulose ethers

The effects of type, molecular weight and concentration of cellulose ethers [methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC)] on pasting properties of wheat flour-based batters were characterized using Brabender Visco-Amylograph. First, three types of cellulose ethers (A4M, E4M, and K4M) were studied. Addition of A4M (methylcellulose) had the strongest effect on pasting properties. There was no significant difference in hot paste stability (HPS) among types of cellulose ethers. Next, MC (1 g/100 g flour) with three distinct numbers average molecular weight (M_n) was further studied. M_n of MC did not affect pasting temperature (PT) and HPS. Conversely, M_n increase up to 41,000 resulted in higher paste viscosity values. Additionally, increase in the concentration of MC resulted in lower PT and higher paste viscosity values; with the exception of viscosity after holding period of slurries containing A4M, which were not significantly different. Only HPS of slurries containing A15 decreased with increase in the concentration.