Effect of essential oils on properties of film forming emulsions and films based on HPMC and chitosan

[EN] Film-forming dispersions (FFD) and films, prepared by incorporating different concentrations of bergamot (BO), lemon (LO) and tea tree (TTO) essential oils into hydroxyproplymethylcellulose (HPMC) and chitosan (CH) were obtained and their physico-chemical properties were characterised. Results showed that the increment of essential oil (EO) content promoted significant changes in the size and surface charge of the FFD particles. As regards the film properties, the higher the EO content, the lower the water vapour permeability and the moisture sorption capacity. In general, the addition of EO into the HPMC or CH matrix leads to a significant decrease in gloss, transparency, tensile strength and elastic modulus of the composite films. Discriminant analyses of obtained data revealed that the polymer type was the main factor which defined the FFD and composite film behaviour. For a given polymer, although both the nature and concentration of the EO influenced FFD behaviour, the concentration played a more important role. In film properties, the discriminant analyses did not reveal different groups associated to the different nature or concentration of the essential oils, although composite films with BO appeared to differ slightly from the rest. (C) 2011 Elsevier Ltd. All rights reserved.The authors acknowledge the financial support provided by Ministerio de Educacion y Ciencia (Project AGL2007-65503). Author L. Sanchez-Gonzalez thanks Ministerio de Educacion y Ciencia (Spain) for a FPU Grant (AP2006-026)Sánchez González, L.; Chiralt, A.; González Martínez, MC.; Cháfer Nácher, MT. (2011). Effect of essential oils on properties of film forming emulsions and films based on HPMC and chitosan. Journal of Food Engineering. 105(2):246-253. https://doi.org/10.1016/j.jfoodeng.2011.02.028S246253105

Effect of amylose:amylopectin ratio and rice bran addition on starchfilms properties

The influence of the amylose:amylopectin ratio on the properties of pea, potato and cassava starch films and the effect of the incorporation of rice bran of two different particle sizes were studied. The structural, mechanical, optical and barrier properties of the films were analyzed after 1 and 5 weeks. The high content of amylose gave rise to stiffer, more resistant to fracture, but less stretchable films, with lower oxygen permeability and greater water binding capacity. Although no changes in the water vapour permeability values of the films were observed during storage, their oxygen permeability decreased. Throughout storage, films became stiffer, more resistant to break, but less stretchable. Rice bran with the smallest particles improved the elastic modulus of the films, especially in high amylose content films, but reduced the film stretchability and its barrier properties, due to the enhancement of the water binding capacity and the introduction of discontinuities.The authors acknowledge the financial support from the Spanish Ministerio de Economia y Competitividad throughout the project AGL2010-20694, co-financed with FEDER founds. Amalia Cano also thanks Spanish Ministerio de Educacion, Cultura y Deporte for the FPU grant.Cano Embuena, AI.; Jiménez Marco, A.; Cháfer Nácher, MT.; González Martínez, MC.; Chiralt Boix, MA. (2014). Effect of amylose:amylopectin ratio and rice bran addition on starchfilms properties. Carbohydrate Polymers. 111:543-555. https://doi.org/10.1016/j.carbpol.2014.04.075S54355511

Effect of hydroxypropylmethylcellulose and chitosan coatings with and without bergamot essential oil on quality and safety of cold-stored grapes

[EN] Biodegradable coatings based on hydroxypropylmethylcellulose (HPMC) or chitosan (CH) with and without bergamot essential oil were applied to table grapes, cv. Muscatel, in order to find environmentally friendly, healthy treatments with which to better preserve fresh fruit quality and safety during postharvest cold storage. Physicochemical properties (weight loss, °Brix, total phenols, antioxidant activity, colour and texture), respiration rates and microbial counts of samples were determined throughout cold storage. The coatings had a significant effect on the development of quality variables, with the additional effect of essential oil addition as a function of the polysaccharide matrix being especially notable. Although incorporation of essential oil resulted in smaller weight losses and a greater antimicrobial effect, it also led to browner samples when using CH. Chitosan coatings containing bergamot oil were more effective than pure CH and HPMC coatings at inhibiting respiration rates. All the coatings improved the mechanical resistance of the samples at the end of storage. The most recommended coating for Muscatel table grapes is CH containing bergamot oil since, despite only contributing slightly to the sample colour, this showed the highest antimicrobial activity and the greatest control of respiration rates with a reasonably good control of water loss during storage. © 2010 Elsevier B.V.The authors acknowledge the financial support provided by Ministerio de Educacion y Ciencia (Project AGL2007-65503).Sánchez González, L.; Pastor Navarro, C.; Vargas, M.; Chiralt, A.; González Martínez, MC.; Cháfer Nácher, MT. (2011). Effect of hydroxypropylmethylcellulose and chitosan coatings with and without bergamot essential oil on quality and safety of cold-stored grapes. Postharvest Biology and Technology. 60(1):57-63. https://doi.org/10.1016/j.postharvbio.2010.11.004S576360

Probiotic fermented almond “milk” as an alternative to cow-milk yoghurt

Probiotics in almond-based matrices were considered as a means of obtaining fermented products which would cover both the current demand for health-promoting foods and for alternatives to standard yoghurts. Firstly, the combined effect of high pressure homogenisation (HPH) and heat treatment on the physical stability of almond “milk” was studied. The beverage was homogenised by applying 62, 103 and 172 MPa (MF1, MF2 and MF3 respectively); MF3 was also combined with two different heat treatments (85 ºC-30 min (LH) and 121 ºC-15 min (HH)). Both microstructure and colloidal stability were analysed in all the processed samples to select the most suitable treatment with which to obtain a stable product. The selected almond milk was then fermented with probiotic Lactobacillus reuteri and Streptococcus thermophilus and the final product was characterised throughout cold storage time (28 days) as to pH, acidity, serum retention and starter viability. A sensory evaluation and probiotic survival to in vitro digestion was also conducted. The results showed that the physical and structural almond-milk properties were affected by both HPH and heat treatments, obtaining the greatest stability in MF3-LH samples. The fermented milk permitted probiotic survivals above the level suggested as minimum for ensuring health benefits during the entire controlled time and, hence, can be considered as a functional food. No differences in the sensory acceptability of the product were found between 1 and 28 storage days. Therefore, a new, functional, fermented product was developed, which was suitable for targeted groups, such as the lactose-intolerant and cow-milk-protein allergic populations.</p

Vegetable milks and their fermented derivative products

The so-called vegetable milks are in the spotlight thanks to their lactose-free, animal protein-free and cholesterol-free features which fit well with the current demand for healthy food products. Nevertheless, and with the exception of soya, little information is available about these types of milks and their derivatives. The aims of this review, therefore, are to: highlight the main nutritional benefits of the nut and cereal vegetable milks available on the market, fermented or not; describe the basic processing steps involved in their manufacturing process; and analyze the major problems affecting their overall quality, together with the current feasible solutions. On the basis of the information gathered, vegetable milks and their derivatives have excellent nutritional properties which provide them a high potential and positive market expectation. Nevertheless, optimal processing conditions for each raw material or the application of new technologies have to be researched in order to improve the quality of the products. Hence, further studies need to be developed to ensure the physical stability of the products throughout their whole shelf-life. These studies would also allow for a reduction in the amount of additives (hydrocolloids and/or emulsifiers) and thus reduce the cost of the products. In the particular case of fermented products, the use of starters which are able to both improve the quality (by synthesizing enhanced flavors and providing optimal textures) and exert health benefits for consumers (i.e. probiotics) is the main challenge to be faced in future studies.</p

Almond milk fermented with different potentially probiotic bacteria improves iron uptake by intestinal epithelial (Caco-2) cells

New fermented almond milks were developed, using different potentially probiotic bacteria, in order to meet the current demand for healthy, versatile non-dairy products. An in vitro digestion/Caco-2 cell model was used to evaluate the effect of both non-fermented and fermented almond milks on the mitochondrial enzymatic activities of enterocytes. Moreover, macrophages were challenged with the in-vitro digested samples and the production of pro-inflammatory biomarkers TNF-a and IL-6 was quantified. Enzymatic activities of cell cultures seemed to be stimulated by the exposure to both fermented and non-fermented almond milks. Both biomarkers decreased (p&lt; 0.05) in fermented almond milks with either B. bifidum or B. longum. Results showed that fermented almond products favored the energetic metabolism of enterocytes and had a lower inflammatory response than non-fermented almond milk, suggesting its benefits for the management of allergies/intolerances. Moreover, the fermentation process enhanced the uptake of iron by Caco-2 cells, especially when using L. rhamnosus and either B. bifidum or B. longum as starters, thus improving the product bioactivity. Therefore, new non-dairy fermented products with functional properties were developed, which might be positioned as alternatives to cow-milk products for sensitized groups of population (allergic and/or intolerant to cow milk or anemic population, among others).</p

Antimicrobial activity of polysaccharide films containing essential oils

Antimicrobial films were prepared by incorporating different concentrations of bergamot (BO), lemon (LO) and tea tree (TTO) essential oils (EO), into chitosan (CH) and hydroxypropylmethylcellulose (HPMC) films. Their antibacterial effectiveness against Listeria monocytogenes, Escherichia coli and Staphylococcus aureus was studied at 10 C during a storage period of 12 days. HPMC-EO and CH-EO composite films present a significant antimicrobial activity against the three pathogens considered. The nature and amount of the essential oils (EO), the structure of the film and the possible interactions which exist between the polymers and active constituents of EO affected the antimicrobial activity of the films. In all film matrices, TTO exhibited the highest antimicrobial activity. A complete inhibition of microbial growth was observed for CH or HPMC-TTO films for E. coli, HPMC-TTO for L. monocytogenes and HPMC-BO for S. aureusThe authors acknowledge the financial support provided by the Conselleria de Empresa, Universidad y Ciencia (Spain) for the project (GV/2007/219) and the Ministerio de Educacion y Ciencia (Project AGL2007-65503). Author L Sanchez-Gonzalez thanks the Ministerio de Educacion y Ciencia (Spain) for an FPU Grant (AP2006-026).Sánchez-González, L.; Cháfer, M.; Hernández Pérez, M.; Chiralt, A.; González-Martínez, C. (2011). Antimicrobial activity of polysaccharide films containing essential oils. Food Control. 22(8):1302-1310. https://doi.org/10.1016/j.foodcont.2011.02.004S1302131022

Effect of high pressure homogenisation and heat treatment on physical properties and stability of almond and hazelnut milks

The effect of high pressure homogenisation (HPH) and heat treatments on physicochemical properties and physical stability of almond and hazelnut milks was studied. Vegetable milks were obtained and homogenised by applying 62, 103 and 172 MPa (MF1, MF2 and MF3, respectively). Untreated and MF3 samples were also submitted to two different heat treatments (85 °C/30 min (LH) or 121 °C/15 min (HH)). Physical and structural properties of the products were greatly affected by heat treatments and HPH. In almond milk, homogenised samples showed a significant reduction in particle size, which turned from bimodal and polydisperse to monodisperse distributions. Particle surface charge, clarity and Whiteness Index were increased and physical stability of samples was improved, without affecting either viscosity or protein stability. Hazelnut beverages showed similar trends, but HPH notably increased their viscosity while change their rheological behaviour, which suggested changes in protein conformation. HH treatments caused an increment of particle size due to the formation oil droplet-protein body clusters, associated with protein denaturation. Samples submitted to the combined treatment MF3 and LH showed the greatest stability