Browse
Abstract
The objective of this study was to research the adaptability of insects in food products. The created hamburger patties were made with pork meat and insect batter (Zophobas morio) in a 50:50 ratio and the color, pH value, water-holding capacity, roasting loss, texture, microbiological traits were studied during ten days of refrigerated storage (5 °C, vaccum packaging, air cooling). Similar products have already existed in European markets, but these are made of 100% of insect meat or with additional vegetables as an ingredient. The mixture of insect and pork could offer a more accepted texture by consumers than the other alternatives. This study showed burger patties with pork meat and insect meat offering a softer texture and darker color, while it could increase the shelf-life of raw product.
Abstract
The objective of our experiment was to investigate the rheological properties of a compound coating depending on the pre-treatment temperature regimes.
Compound coating samples were measured at six different temperatures with 2 °C resolution between 40 and 50 °C. One part of melted samples was measured by RV1 rotational rheometer at the actual melting temperatures and the other part of melted samples was filled into 9 × 9 × 9 mm cubes molds. These cubes were cooled 24 h in freezer (−18 °C) and next day the samples were warmed to room temperature for 3 hours with different temperature combinations. The solid cubes were measured with Texture Profile Analysis (TPA) test by SMS TA-XTplus Texture Analyzer at room temperature.
Results show the effect of pre-treatment on the viscosity of the coating. Furthermore, significant differences were found among the samples cooled with different cooling methods. Our results stress the importance of the correct handling of the materials for confectioners.
Colour of grapevine (Vitis vinifera L.) accessions influenced by the length of cold storage •
Grapevine berry colour measurement
Abstract
Colour is one of the most important phenotypic characters of the table grape cultivars, which has high importance in the consumer's preference. This morphological trait is variable and not consistently uniform within a cultivar or even a bunch. Between harvest and consumption fruits are stored for several weeks which time is influencing the colour of the berry. In this study 10 grapevine accessions (Agaphante, KM98, Korai piros veltelini, Korona, Pinot gris, Pozsonyi, Ros de Minis, Tramini piros, T9, Zenit) were collected from the germplasm collection of the Research Institute for Viticulture and Oenology of the National Agricultural Research and Innovation Centre of Kecskemét. The samples were investigated by ColorLite Sph850 spectrophotometer. The colour of 30 berries per accessions were measured in 3 replicates per berry. The aim of this study was to evaluate the colour and the effect of cold storage. L✻, a✻, b✻ values of each accessions were evaluated after the sampling and until a visible reduction in the quality of the grapes, at most 4 weeks with 1-week intervals from the harvest. Results showed that there is a significant difference among the cultivars in the L∗, a∗, b∗ values. The length of cold storage also has a significant effect on the colour of the accessions as the values are changing in some cases of the 1-week storage period.
Abstract
The high antioxidant capacity of tea is well-known, but the effect of flavorings like honey or lemon has been less studied. Their antioxidants can interact with each other, the global result being also affected by the brewing temperature.
The combined effect of heat (55 and 80 °C) and flavorings (acacia and honeydew honeys, lemon juice) on the total polyphenol, total flavonoid content and antioxidant capacity of black and green teas was studied.
In many cases higher antioxidant capacity was obtained at 80 °C. Teas flavored with honeydew honey had higher antioxidant capacity than those containing acacia honey. Addition of lemon decreased the antioxidant capacity of tea with honey. No synergies were confirmed in any of the compositions investigated. Vitamin C content of lemon-containing black tea was reduced by half at 80 °C compared to tea brewed at 55 °C; while honey was shown to partly prevent this loss of ascorbic acid.
Abstract
This work aimed to study the antimicrobial activity of eight various components of plant origin on the growth of Pseudomonas lundensis and Listeria monocytogenes. Different in vitro methods were used: agar plate diffusion, micro atmosphere, agar hole diffusion, micro-dilution, and gradient-plate method. In the first agar plate assay, p-cymene and γ-terpinene did not inhibit the growth of the tested bacteria therefore they were not used in further experiments. Both α-pinene and limonene were only partially effective, but these were screened only for their partial inhibition. The other four components completely inhibited the growth of the tested bacteria. Using the agar-well diffusion method showed that carvacrol and thymol were found to be the most effective active components, thymol had minimum inhibitory concentration (MIC) at 1.563 mg/mL, however, in the case of carvacrol, MIC was 7.813 μL/mL. Additionally, eugenol and camphor show the same results but in higher concentrations. Gradient plate method was used to determine MIC values, in which it has been proved that carvacrol and thymol possess strong antimicrobial activity, no growth of tested bacteria was observed with carvacrol (100 μL/mL), while thymol exhibited MIC of 1.887 mg/mL against P. lundensis and 0.943 mg/mL needed to show complete inhibition of Listeria monocytogenes. Further experiments are needed to determine the optimum concentrations of the active components against P. lundensis and L. monocytogenes.
Abstract
Application of cold storage temperatures below optimum induces a high risk and threat of chilling injury (CI) in the case of sensitive commodities. Sweet pepper belongs to this group of vegetables, so our main objective was to investigate and monitor the effect of non-optimal temperatures (2.5 and 5 °C) induced stress (chilling injury) on kápia type sweet pepper (Capsicum annuum L.) during its postharvest storage by nondestructive quality measuring methods. Fresh, semi-matured (reddish-green colored) samples of ‘Kapitány F1’ cultivar were stored at 2.5, 5 and 10 °C for 7 d followed by 7 d shelf-life. Nondestructive texture measurements were carried out by a purpose built tabletop acoustic stiffness device. Surface color and chlorophyll content related quality indices were evaluated by a chroma meter, a DA-meter® and a chlorophyll fluorescence imaging system. High resolution digital pictures were captured and analyzed for possible CI defects by means of surface color values (normalized RGB, hue and saturation). According to our results, the evaluated quality indices (DA-index®, acoustic stiffness coefficient, surface color parameters; F0, Fm, Fv and Fv/Fm chlorophyll fluorescence parameters) clearly represented the temperature dependent quality changes during low temperature storage, subsequently followed by ambient shelf-life. Samples stored under and at 5 °C showed the chilling temperature stressed symptoms of delayed and partly retarded postharvest ripening, even under simulated shelf-life conditions, but without the onset and manifestation of the characteristic visible symptoms of chilling injury. This may raise doubts and suggest possible future research areas regarding the role of non-optimal cold storage temperatures induced stress, the effect of chilling injury contributing factors and consequences.
Abstract
In the agri-food industry world, billions of tons of waste are produced every year. This represents both a direct loss (due to the failure to exploit their potential value, and their nutritional and energy content) and indirect loss, due to their necessary treatment and/or disposal. Some substances contained in the wastes, of potential high value, can be recovered by means of extraction. Conventional extraction processes involve the use of solvents, which end up requiring an additional process of separation from the solute identified as the desired product. In recent years, extraction techniques have been proposed without the use of solvents. This work compares the performance of two microwave cavities used for extraction operations, both working at 2.45 GHz.
A calorimetric analysis performed by following the heating rate and temperature evolution in rack of 25 beakers filled with 25 mL of water, coupled with the solution of the heat transfer balance in the system, allowed to build the spatial distribution of the electromagnetic power dissipated as heat in each of the beakers. Fluid-dynamics aspects related to the recovery of the vapour phase produced during the extraction were also analyzed, with particular emphasis on the mean residence time of the vapour fraction in the extraction chamber as a function of its configuration.
Abstract
The aim of this study was to evaluate the effect of edible coating on hydroponic strawberry during storage. Strawberries were coated with either 1% or 1.5% chitosan (CS) or with solution containing 1.5% chitosan and 0.5% calcium gluconate (CaGlu). After treatment, samples were stored at 10 °C, RH 90% for 10 days. The weight loss, soluble solid content, firmness, surface color, pH, and percentage of decay were evaluated each day during the experiment. It was observed that coating extended the postharvest life of hydroponic strawberry compared to control. Fungal growth occurred on control group at the 5th day and fruit treated with 1% CS at the 8th day of the storage period, whereas no visible sign was detected for other treatments. Soluble solid content and pH showed only minor change for all samples. Weight loss of coated fruit was below 6% after 10 days of storage, whereas the weight loss of control samples was around 10% at the end of measurement. Moreover, coating could maintain the firmness of strawberry compared to the control. The combination of chitosan and calcium gluconate showed the potential for prolonging the storage period of hydroponic strawberry till 10 days without decay, whereas the control sample had more than 60% of rotted fruit.
Abstract
The effect of three types of emulsifiers (polyglycerol monostearate ester – E475, sucrose stearate ester – E473 and modified inulin palmitate ester – HP-25) on the starch retrogradation in sponge cake (SC) during storage was investigated. The method of differential scanning calorimetry (DSC) was applied to determine the changes in the starch retrogradation during the staling process. The retrogradation temperature and the enthalpy of the endothermic transition decreased when emulsifiers were added. The lowest values of the enthalpy for the whole storage period were found for SC with 1% HP-25. The methods of differential thermal analysis (DTA) and thermogravimetry analysis (TGA) showed significantly bigger (1.43 times) amount of strongly bound water in the crumb of the SC with E475 and HP-25 in comparison to the control sample on the sixth day of storage. Based on our results, emulsifiers possessed retarding effect on the starch retrogradation and extend the shelf-life of the SC.
Abstract
One of the biggest challenges of raspberry production in Hungary nowadays is reducing the unfavorable effects of climate change. The maturation phase of main varieties within this region falls in a period of extremely high temperature and atmospheric drought detaining desirable fruit growth. Dedicated plant breeding alone is not enough. An immediate action is required. There has been a need for physical protection against excessive direct radiation. In order to restore, or even save the domestic raspberry production and market, introducing of greenhouse or polytunnel solutions are needed. Experimental plantations of three different raspberry varieties were set in two repetitions: covered and uncovered versions. Each cover has characteristic interaction with light which can generate different environmental conditions and also differences in plant growth and fruit quality. Besides the monitoring of elementary biological indicators, a wide range of sensors (temperature, humidity, solar irradiation) was used to identify differences and to find the optimal tunnel material for maximal plant productivity. Within the framework of the project we also tested a portable spectroradiometer and a snapshot imaging camera to study the practical value of proximal sensing in water- and photosynthetic light use efficiency and vitality mapping.
