Search

This study investigated properties of starch-based edible films with oregano and black cumin essential oil addition. Essential oils addition positively affected film swelling (decreased due to essential oil addition), mechanical properties (tensile strength decreased while elongation at break increased), and water vapor barrier properties (decreased along with essential oils addition). Control film did not have any biological activity, which proves the need for essential oils addition in order to obtain active packaging. Oregano oil was more effective in terms of biological activity. Endothermal peak, above 200°C, represents total thermal degradation of edible films. Diffraction pattern of control film showed significant destruction of A-type crystal structure. Addition of essential oils resulted in peak shape change: diffraction peaks became narrower. Principal Component Analysis has been used to assess the effect of essential oils addition on final starch-based edible films characteristics with the aim to reveal directions for the film characteristics improvement, since the next phase will be optimal film application for food packaging.

Pumpkin seed protein isolate (PSPI) was enzymatically hydrolysed by pepsin to obtain pumpkin seed protein hydrolysate, PSPH. Investigation on solubility, interfacial and emulsifying properties of both PSPI and PSPH was conducted under different conditions of pH (3-8) and ionic strength (0-1 mol/dm3 NaCl). PSPI had the lowest solubility, i.e. isoelectric point (pI), at pH 5. PSPH had higher solubility than PSPI over whole range of pH and ionic strengths tested. Decrease in surface and interfacial tension evidenced that both PSPI and PSPH adsorb at air/protein solution and oil/protein solution interface. Emulsions (20 % oil in water) stabilized by 1 g/100cm3 PSPI or PSPH solution were prepared at pH 3, 5 and 8 and ionic strength of 0 and 0.5 mol/dm3 NaCl. PSPH stabilized emulsions from coalescence at all pH and ionic strengths tested. PSPI was able to stabilize emulsions at pH 3 and 0 mol/dm3 NaCl, and at pH 8 regardless of ionic strength, while emulsions at pH 5 and both 0 and 0.5 mol/dm3 NaCl and at pH 3 when ionic strength was increased separated to oil and serum layer immediately after preparation. All emulsions were susceptible to creaming instability. [Projekat Ministarstva nauke Republike Srbije, br. III 46010]

The application of biopolymer films and coating to food products represents a new approach to reduce r migration of moisture, oxygen, carbon dioxide, aromas, and oil in or out of food. Also, biopolymer films, as packaging materials, need to enhance appearance of food and to improve mechanical integrity. In order to facilitate handling and application films must be strong, but flexible enough. Addition of plasticizer could modify the flexibility of biopolymer films. It is known that guar-xanthan can improve the flexibility of polysaccharides films. Therefore, the objective of this study was to examine the influence of guar-xanthan on characteristics of pumpkin oil cake (PuOC) films, with emphasis on the flexibility of the film. Two approaches of guar-xanthan addition in the pumpkin oil cake were applied - stirring with laboratory stirrer and using of ultra turrax homogenizer. The results showed that guar-xanthan improved physical and mechanical properties of PuOC films, but only if film-forming solution was homogenized by ultra turrax. The films with guar-xanthan slightly improved mechanical properties - tensile strength and elongation at break, water content, solubility and swelling properties, but were much easier for handling.

The aim of this study was to evaluate bioactivity of chitosan film with incorporated caraway essential oil by measuring antioxidant and antimicrobial activity. A Fourier transform infrared spectroscopy was used to determine the potential interaction of functional groups of chitosan film and incorporated caraway essential oil. New detected peaks and main shifts in the peaks of chitosan spectra are attributed mainly to presence of s-(+)-carvone and limonene, the main components of caraway essential oil. The antioxidant activity of chitosan film was analyzed by DPPH method. Chitosan film without incorporated caraway essential oil showed the lowest scavenging ability (29.95%, after 24 h). The addition of different concentrations of caraway essential oil into chitosan film significantly enhanced antioxidant activity of pure chitosan film, reaching the maximum of 95%. ASTM E 2149 - 01 method was performed to evaluate the antimicrobial activity of chitosan films. The reduction of bacteria cell number in contact with examined films was tested on Gram-positive bacteria Staphylococcus aureus and Listeria monocytogenes and Gram-negative bacteria Escherichia coli and Salmonella Typhimurium. The most sensitive bacteria was Staphylococcus aureus and the most resistant bacteria was Salmonella Typhimurium for all tested films. These results suggested that incorporation of caraway essential oil into chitosan film significantly improved its antioxidant and antimicrobial activity. The film showed a great potential to be used as an active packaging material.

In this work, caraway or oregano essential oils were added to the cast chitosan film in an attempt to design a natural, biodegradable, bioactive (antioxidant and antimicrobial) packaging film. When the structure of the tested films was analyzed with Fourier transform infrared spectroscopy, no significant differences were found between the chitosan film with and without essential oils of caraway or oregano. The lowest antioxidant activity, based on the scavenging of the stable DPPH• free radical, was detected for the chitosan film without oil addition, going from 11.64%, after 2.5 h to 28.96%, after 24 h. When the caraway essential oil was added to the chitosan film, the antioxidant activity was increased (p

The partitioning of acid protease produced by submerged fermentation of Penicillium roqueforti in the aqueous two-phase system polyethylene glycol/sodium phosphate was studied. In the system with 15% polyethylene glycol 4000/25% NaH2PO4 favourable partition coefficient and the top phase yield were obtained, 2.651 and 56.51%, respectively. The purification of acid protease from crude enzyme was optimized by optimizing separation factor. Completely randomized factorial design was applied and the system 15.54% PEG 4000/20% NaH2PO4 appeared to be optimal. Statistically calculated separation factor of 3.553, was similar to the experimentally obtained value (3.084), which indicates the possible application of the factorial design onto ATPS partition and purifycation.

The article focuses on the extraction of ten phenolic acids from black cumin ( Nigella sativa L.), pomegranate ( Punica granatum L.) and flax ( Linum usitatissimum L.) seed meals. The extracts have been fractionated as free, esterified and insoluble-bound phenolic compounds and quantitatively determined by HPLC- PDA. The analysed meals can be utilised for obtaining valuable phenolic acids. However, the distribution of phenolic compounds varies depending on the meal source. The insoluble-bound fraction has been the richest for the black cumin meal, both qualitatively and quantitatively, containing all ten analysed phenolics. In the pomegranate meal, the main phenolic has been gallic acid, accounting for nearly 48% in free form. The esterified form of the flaxseed meal has been abundant with ferulic (1025.44 ± 3.99 mg kg−1 dry weight), caffeic and p-coumaric acids. The total amount of phenolic acids would be underestimated if only free fractions would be taken into account, while neglecting esterified (for the pomegranate and flax meals) and insoluble-bound fractions (for the black cumin and pomegranate meals). [ABSTRACT FROM AUTHOR]

In this work, a simulated gastrointestinal digestion of pumpkin oil cake protein hydrolysate prepared by alcalase (AH) was studied to evaluate the impact of the main gastrointestinal proteases on its antiradical and angiotensin I-converting enzyme (ACE) inhibitory activity. The in vitro digestion was performed in a model system under optimized reaction conditions, first by pepsin and then with α-chymotrypsin and trypsin, simultaneously. The treatment with the gastrointestinal proteases led to a significant increase of the degree of hydrolysis, up to 55.95 ± 3.1% in the final digest. After the digestion, the 2,2-azinobis3-ethylbenzo-thiazoline-6-sulphonic acid radical cation activity of AH was increased from 7.59 ± 0.1 to 10.25 ± 0.3 mM trolox equivalent antioxidant coefficient/mg ( p < 0.05), while the ACE inhibitory activity was not affected, being 74.29 ± 1.25% (IC50 = 0.404 ± 0.014 mg/ml) ( p>0.05) in the final digest. These results showed an advantage of AH to increase the antiradical and resist ACE inhibitory activity during digestion by main gastrointestinal proteases, appearing as promising bioactive food ingredient. [ABSTRACT FROM AUTHOR]

In this paper, active edible packaging material was prepared and designed for potential application in sausage preservation. Material was prepared from chitosan with the addition of four oleoresins: garlic, black pepper, caraway and cinnamon. Antioxidative and antimicrobial activities of prepared films were tested and the film with optimal activity was further analysed as a food-packaging material. Chitosan film with added four oleoresins at a volume concentration of 2% (0.5% garlic, 0.5% black pepper, 0.5% caraway and 0.5% cinnamon) was found to be an effective antioxidant and antimicrobial material. Tensile strength and elongation at break showed weakening of the chitosan film with the addition of oleoresins. Water sensitivity of the chitosan film was lowered with oleoresins addition, considering film water content and swelling ability. Similar to pure chitosan film, chitosan film with oleoresins had very good barrier properties to oxygen and air, which could be compared to commercial barrier and high barrier films. The high water vapour permeability of the chitosan film was not decreased with the addition of oleoresins. Physical-mechanical properties and water vapour-barrier properties stay main possible drawbacks in application of chitosan film with oleoresins as self-standing packaging material, but its application would be possible as active coating and in combination with compatible materials. [ABSTRACT FROM AUTHOR]