Real Food Models Research Articles

Impact of Fat Replacement by Using Organic-Candelilla-Wax-Based Oleogels on the Physicochemical and Sensorial Properties of a Model Cookie.

Oleogelation is an alternative process to improve the nutritional properties of food by creating soft-matter structures with the same functionality as commercial fats (shortenings). In this study, oleogels were produced by adding organic candelilla wax at 3% (OC03), 6% (OC06), and 9% (OC09) to extra-virgin linseed oil, and then characterized by their physicochemical properties. Furthermore, the physicochemical and sensorial properties of five cookie formulations were evaluated. Organic candelilla wax influenced the oleogel formulations, giving higher values of color (L* and b*), texture, acidity index, and melting point. In the cookie formulations, the luminosity values decreased when the percentage of oleogel was increased; reddish trends were obtained (a* values) for the cookie where 70% of the fat was replaced by the oleogel (C70), and more yellow trends were obtained (b* values) for C100. The moisture content was higher in cookies with oleogels, but it was within quality limits. The percentage of fat migration was lower in cookies with a mixture of fats and oleogels. In terms of hardness, the substitution of oleogels resulted in softer cookies. In terms of the sensory evaluation, the most accepted cookie was C70. Therefore, this study demonstrates the possibility of using organic-candelilla-wax-based oleogels in a real food model rich in unsaturated fats.

Performance of bacterial nanocellulose packaging film functionalised in situ with zinc oxide: Migration onto chicken skin and antimicrobial activity

Zinc oxide nanoparticles (ZnO) are cost-effective antimicrobial agents with great potential for the active packaging industry. Bacterial NanoCellulose (BNC) features a porous fibre network, with high absorption capacity, flexible and with good mechanical properties, suitable as a carrier of active agents. In this work, BNCZnO films were developed and optimized regarding the particle size and ZnO concentration. The NaOH dropwise addition to BNC membranes immersed in Zn(CH3COO)2-PVOH enabled the production of ZnO nanoparticles with an z-average of 144 nm and a low polydispersity index. High ZnO incorporation (∼27%mZn/mBNCZnO) was obtained, with uniform distribution all over the BNC membranes. These composites were then characterized and evaluated for Zn migration using food simulants (10%, 20%, and 50% ethanol) with results lower than the limit. Migration into chicken skin, as a real food model, was low at 4 °C but exceeded the migration limit at 10 and 22 °C. Zn migration was also found to be temperature and pH dependent. When applied to chicken skin, BNCZnO was effective against E. coli, Salmonella (0.5–1.0 log reduction), and Campylobacter spp. (2.0 log reduction), indicating its potential for active packaging applications.

Spinach (Spinacia oleracea) microgreen prevents the formation of advanced glycation end products in model systems and breads

The formation of advanced glycation end products (AGEs) in daily diets poses a great threat to human health, since AGEs are closely related to some chronic metabolic diseases. In this study, we investigated the antiglycative capabilities of some popular microgreens in chemical model. Our data indicated that baby spinach (Spinacia oleracea) had the highest antiglycative activity during 4-wks incubation, with antioxidation being the main action route. Moreover, a bread model was set up to evaluate its antiglycative potential in real food model. The results showed that the fortification of baby spinach in bread significantly inhibited AGEs formation, with acceptable taste and food quality. Further study revealed that the antiglycative components were mainly distributed in leaves, which were separated via column chromatography and tentatively identified as chlorophyll derivatives. In summary, this study highlighted the antiglycative benefits of baby spinach which can be developed into healthy functional foods.

Smart monitoring of gas/temperature changes within food packaging based on natural colorants.

The development of smart packaging and innovation in common food packaging technology will greatly help to meet market needs, including consumer preference for "safe" foods, high-quality products and mitigate the negative environmental impacts of food packaging. In addition, consumers' tendency to use natural ingredients such as pigments and biopolymers has provided the basis for their application in the food industry, including smart food packaging. Hence, smart packaging in addition to protecting food products against environmental damage can also reveal a sign (colorimetric, chemical, electric, etc.) in real time in response to any changes in the packaging conditions and food quality. This comprehensive review emphasizes on the gas/temperature-sensitive smart films based on natural colorants and their key applications in the food packaging systems. Technological considerations associated with the natural colorant-responsive films, smart packaging, biopolymers, and importance of natural colorants versus synthetic dyes are investigated. In practice, the most common designed colorimetric indicators for monitoring gas and temperature changes and application of relevant smart films in real food models have also been discussed. Gas and time-temperature indicators provide a rapid, reliable, and online assessment and a visual indication of the food product quality level, usually through a color change, which is directly related to gas and temperature conditions during distribution and storage of relevant food products. However, future studies need to consider main points such as cost, consumers' acceptance, and confidence, regulatory aspects (i.e., labeling) and multifunctionality of smart packaging to be commercially sustainable.

Production and characterisation of biodegradable PLA nanoparticles loaded with thymol to improve its antimicrobial effect

Thymol is widely recognised as an antibacterial compound. However, its use in food technology is hindered by its high volatility, its light sensitivity and its low solubility in water. To overcome these drawbacks, the preparation of nanoparticles using polylactic acid (PLA) is proposed in this study.The average size of the nanoparticles and thymol encapsulation efficiency parameters were studied using different PLA and thymol concentrations. Furthermore, the morphology, the storage stability of the nanoparticles at several pHs and the in vitro thymol release profile were also studied, as well as their thermal degradation profile. Finally, their antimicrobial activity on a real food model was measured, using for this purpose apple pieces previously inoculated with E. coli.The PLA was found to be the key variable in optimizing the nanoparticle preparation, producing spherical nanoparticles with a thymol encapsulation efficiency of 60.3 ± 8%. These nanoparticles showed a high storage stability at several pHs and improved antimicrobial properties in comparison with the non-encapsulated thymol.

Camel milk protein hydrolysates with improved technofunctional properties and enhanced antioxidant potential in in vitro and in food model systems

Camel milk protein hydrolysates (CMPH) were generated using proteolytic enzymes, such as alcalase, bromelain, and papain, to explore the effect on the technofunctional properties and antioxidant potential under in vitro and in real food model systems. Characterization of the CMPH via degree of hydrolysis, sodium dodecyl sulfate-PAGE, and HPLC revealed that different proteins in camel milk underwent degradation at different degrees after enzymatic hydrolysis using 3 different enzymes for 2, 4, and 6 h, with papain displaying the highest degradation. Technofunctional properties, such as emulsifying activity index, surface hydrophobicity, and protein solubility, were higher in CMPH than unhydrolyzed camel milk proteins. However, the water and fat absorption capacity were lower in CMPH compared with unhydrolyzed camel milk proteins. Antioxidant properties as assessed by 2,2-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activities and metal-chelating activity were enhanced after hydrolysis, in contrast to ferric-reducing antioxidant power which showed a decrease after hydrolysis. The CMPH were also tested in real food model systems for their potential to inhibit lipid peroxidation in fish mince and grape seed oil-in-water emulsion, and we found that papain-produced hydrolysate displayed higher inhibition than alcalase- and bromelain-produced hydrolysates. Therefore, the CMPH demonstrated effective antioxidant potential in vitro as well as in real food systems and showed enhanced functional properties, which guarantees their potential applications in functional foods. The present study is one of few reports available on CMPH being explored in vitro as well as in real food model systems.

Green Extraction from Pomegranate Marcs for the Production of Functional Foods and Cosmetics.

The aim of this study was to investigate the potential of retrieving polyphenolic antioxidants directly from wet pomegranate marcs: the fresh by-products obtained after pomegranate juice processing. These by-products mainly consist of internal membranes (endocarp) and aril residues. Even if they are still edible, they are usually discharged during juice production and, thus, they represent a great challenge in an eco-sustainable industrial context. Green technologies, such as ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE), have been employed to convert these organic residues into recycled products with high added value. UAE and MAE were used both in parallel and in series in order to make a comparison and to ensure exhaustive extractions, respectively. Water, as an environmentally friendly extraction solvent, has been employed. The results were compared with those ones coming from a conventional extraction. The most promising extract, in terms of total polyphenol yield and radical scavenging activity, has been tested both as a potential natural additive and as a functional ingredient after its incorporation in a real food model and in a real cosmetic matrix, respectively. This study represents a proposal to the agro-alimentary sector given the general need of environmental “responsible care”.

Relative Effects of Sensory Modalities and Importance of Fatty Acid Sensitivity on Fat Perception in a Real Food Model

IntroductionFat can be perceived through mouthfeel, odour and taste, but the influence of these modalities on fat perception remains undefined. Fatty acids are stimuli and individual sensitivity to fatty acids varies. Studies show association between fatty acid sensitivity, dietary intake and BMI, but results are conflicting. Therefore, this study examined this association, and the effect of modalities on fat perception.MethodsTwo sub-studies were conducted. In study 1 (n = 46), fat intensity was assessed by milk/cream mixtures varying by five fat levels. Fat intensity was rated under four conditions: mouthfeel odour-masked, mouthfeel-masked, odour masked and with no masking. Mouthfeel masking was achieved using thickener and paraffin, odour masking using nose-clips. Fatty acid sensitivity was measured by 3-AFC staircase method using milk containing oleic acid (0.31–31.4 mM). In study 2 (n = 51), more fat levels were added into the intensity rating. A 2-AFC discrimination test was used to confirm whether fat levels could be distinguished. In the sensitivity test, a wider range of oleic acid was included. ResultsFat intensity was rated higher without nose clips (p < 0.0001), implying that odour increased fat perception. Mouthfeel-masked samples were rated higher, showing that increased viscosity and lubricity enhanced fat perception (p < 0.0001). Participants could distinguish fat levels based on “taste” in rating tests and 2-AFC tests. Participants were divided into high-/medium-/low-sensitivity groups. No significant difference was found in fat intensity between groups; however, the high-sensitivity group discriminated more fat levels. No association between sensitivity groups, nutrient intake or BMI was found.ConclusionMouthfeel and odour can enhance fat perception. Fat level can be discriminated based on taste.Electronic supplementary materialThe online version of this article (doi:10.1007/s12078-016-9211-5) contains supplementary material, which is available to authorized users.

اثر ضدمیکروبی فیلم زیست‌فعال زئین حاوی اسانس آویشن علیه Escherichia coli و listeriainnocua طی نگهداری سالاد الویه

Introduction: Antimicrobial packaging is a novel preservation technology that is designed base on releaseing of active agents incorporated with the packaging polymer into the packaged food or the surrounding environment for improveing the quality and food safety. Zein, water insoluble proteinof cornof corn, reported to be thermoplastic material with high tensile strength, excellent hydrophobic film, biodegradability.Zataria multiflora Boiss. (Z) is a thyme-like plant belonging to the Laminaceae family that geographically grows wild in central and southern parts of Iran. Antimicrobial activity of Z essential oil (ZEO) has been successfully tested against foodborne pathogens. Most of the studies on antimicrobial packaging mainly focused on the initial screening of newly developed films for ZEO in laboratory media and quantifying the bacterial reductions obtained during storage for different types of packaged food products. it is really important to know the variation in antibacterial activity of the agents when incorporated into the packaging film from its original activity in order to establish the levels that need to be incorporated for effective bacteria inhibition, hence The aims of the present study were to investigate the antimicrobial potential of ZEO incorporated zein film against pathogenic microorganisms inoculated in olivier saladto provide evidence of their applicability in the design of active food packaging systems. Materials and method: Z was collected in the Shiraz province of Iran and extected by using clevenger type apparatus. Chemical composition ZEO was analyzed by gas chromatography.Antibacterial activity of ZEO was studied in the liquid (direct contact) and solid media (vapour phase) against Listeriainnocua and Escherchia coli . Zein powder was dissolved in a hydro alcoholic solution to obtain 16% (w/w) films forming solutions. The solution was stirred for at 80 °C using a magnetic stirrer hotplate. Glycerol (15%) was added to the solution and stirred again for 8 min at 30°Cm, then ZEO was added to the polymer solutions in 5% and 10% with respect to polymer content and stirred for 8 min. Films were obtained by casting, the film forming solutions were extended over it using an extension bar and introduced in a drying tunnel equipped with a heat of 2500 W during 20 min. Control zein films were prepared without active agent. To evaluate the efficacy of developed zein films was tested against two bacteria. Prior to the experiment, a loop of each strain was transferred to 10 ml of TSB and incubated at 37 ˚C for 18 h to obtain early stationary phase cells and100 µl of microorganism were inoculated into tubes with 10 ml of TSB. The tubes were then incubated at 37 °C for 18 h and 4 °C for 5 days. As control, zein film without active agent was also used in every experiment. Antibacterial activity of zein films containing 10% ZEO were evaluaterd for packaing of olivier salad as a real food model for 6 days, by performing serial dilutions with peptone and subsequent plating in Palcam Listeria Selective Agar and Brilliant Green Agar for ListeriainnocuaandEscherchia colirespectively. Plates were incubated at 37 °C for 48 hours. Results and Discussion: GC–MS analysis showed thatthe major compound of ZEO was carvacrol (45.22%). The antimicrobial effects of ZEO in the vapor phase against Escherchia coliand Listeriainnocuaby using the disk diffusion methodshowed that the25 µg of ZEO produced a visible decrease in microbial density retraction zone (+). No inhibition was observed with the addition of lower amounts of the antimicrobial agents, therefore 25 µg was the minimum inhibitory concentration (MIC).Activezein films containing 5% ZEOweren’t able to inhibit the growth of the two bacteria in the vapour pase.. When the concentrations of ZEO was increased to 10%, only active films with a diameter of 80 mm (50.24 cm2)provided a retraction zone (+) against Listeriainnocuaand E. coli. These values were indicative that incorporation of the agent in the zein films produced weaker vapor phase inhibition than its incorporation in the paper disk.The results of this studied showedthat films with 5% ZEO caused a growth reduction of 1.17 log againstListeriainnocuaand 1.14 log against Escherchia coli, while 10% ZEO produced reductions of 2.16 and 2.64 log against Listeriainnocua, Escherchia colirespectively. There was no significantdifference betweenlog reduction values of ZEO incorporated in zein films against Listeria innocuaand Escherchia coli. And also in the liquid media with increasing the concentration of ZEO in zein films, the log reduction values were increased against both bactreia. Despite of the excellent antibactrerial effect of ZEO in zein films in direct contact, bio active zein films were not effective enough for reducing the contamination of packaged Olivier.

Comparison of growth limits of Listeria monocytogenes in milk, broth and cheese

To determine growth initiation differences of Listeria monocytogenes between a cheesemaking context, milk and tryptic soy broth (TSB). A laboratory-scale cheese was made with a mix of two strains of L. monocytogenes at four initial pH values, five water activity (a(w)) values and two contamination levels at 30°C. Counts of L. monocytogenes were determined at time 0 and after 8h of cheese manufacture. Milk and TSB at the same pH and a(w) conditions were inoculated with the L. monocytogenes mix in multi-well plates. Growth was determined by plating each well onto Agosti & Ottaviani Listeria Agar after 8h of incubation at 30°C. Each condition was repeated six times, and growth initiation probability was modelled with logistic regression models. Growth initiation boundaries were obtained for each matrix type. The results showed that the growth limits were matrix dependent. In the three matrix types, a(w) was the most important factor affecting the probability of growth initiation. Contamination level affected growth TSB and cheesemaking conditions. The interface wideness and position in cheese, milk and TSB were dissimilar, indicating that the use of models evaluated in TSB or milk could not be used to predict the behaviour of L. monocytogenes under cheesemaking conditions. Predictive models generated in liquid media are not necessarily adaptable to solid food, and the generation of real food models is necessary.

Antimicrobial activities of tapioca starch/decolorized hsian-tsao leaf gum coatings containing green tea extracts in fruit-based salads, romaine hearts and pork slices

The antimicrobial activities of edible coatings based on a tapioca starch/decolorized hsian-tsao leaf gum (dHG) matrix with various green tea extracts (GTEs) were evaluated. Its effect on the shelf-life extension of fruit-based salads, romaine hearts, and pork slices were investigated as well. Three types of GTEs from hot water (80 °C) (W), 40% (E4) and 80% (E8) ethanol were prepared. It was found that all GTEs showed pronounced inhibition on Gram positive bacteria in agar media, including Staphylococcus aureus BCRC 10781, Bacillus cereus BCRC 11778 and Listeria monocytogenes BCRC 14848, but not on Gram negative bacteria, such as Escherichia coli DH10β and Salmonella enteria BCRC 10747. The antimicrobial activities increased with increasing GTEs concentration (1, 2 and 5%), but did not differentiate significantly in terms of the effect of extraction solvents. When various GTEs (1%) were added to an edible coating formulation based on 1.35% tapioca starch + 0.15% dHG + 0.225% glycerol, pronounced antimicrobial activity on Gram positive bacteria was also observed as evaluated by using cylinder diffusion and antimicrobial migration tests. It was believed that the active compounds in green tea extracts could leave the coating matrix and migrate to increase the non-growth area. When being sprayed on various real food models, all tapioca starch/dHG coatings containing GTEs could successfully reduce the aerobic counting and growth of yeasts/molds by 1 to 2 log cycles in fruit-based salads, as compared to the control sample. Furthermore, during refrigerated storage of romaine hearts and pork slices for 48 h, tapioca starch/dHG coatings with E4 extracts demonstrated pronounced antimicrobial activity against Gram positive bacteria (4–6 log cycles reduction), followed by W extracts and E8 extracts in a decreasing order. Such results implied the high efficacy of antimicrobial migration of tapioca starch/dHG coatings containing GTEs and their application potentials on foods.