Melissopalynology is an important analytical method to identify botanical origin of honey. Pollen grain recognition is commonly performed by visual inspection by a trained person. An alternative method for visual inspection is automated pollen analysis based on the image analysis technique. Image analysis transfers visual information to mathematical descriptions. In this work, the suitability of three microscopic techniques for automatic analysis of pollen grains was studied. 2D and 3D morphological characteristics, textural and colour features, and extended depth of focus characteristics were used for the pollen discrimination. In this study, 7 botanical taxa and a total of 2482 pollen grains were evaluated. The highest correct classification rate of 93.05% was achieved using the phase contrast microscopy, followed by the dark field microscopy reaching 91.02%, and finally by the light field microscopy reaching 88.88%. The most significant discriminant characteristics were morphological (2D and 3D) and colour characteristics. Our results confirm the potential of using automatic pollen analysis to discriminate pollen taxa in honey. This work provides the basis for further research where the taxa dataset will be increased, and new descriptors will be studied.
Studies dealing with the development of edible/biodegradable packaging have been gaining popularity since these commodities are marked as being ecofriendly, especially when byproducts are incorporated. Consequently, this study aimed at the development of chitosan-based coatings with plant byproducts. Their sensory properties, colour attributes, occurrence of cracks in microstructure and biodegradability were analysed. Coatings containing grape and blueberry pomace had statistically significantly (p < 0.05) higher levels of colour intensity. Coating samples were characterised by lower aroma intensity (3.46–4.77), relatively smooth surface (2.40–5.86), and low stickiness (2.11–3.14). In the overall hedonic evaluation, the samples containing parsley pomace in all concentrations and a sample containing 5% grape pomace achieved a statistically significantly (p < 0.05) better evaluation (5.76–5.93). The lowest values of the parameter ΔE2000 were recorded for the sample containing 5% parsley pomace (3.5); the highest was for the sample with 20% blueberry pomace (39.3). An analysis of the coating surface microstructure showed the presence of surface cracks at an 80 K magnification but the protective function of the edible coating was not disrupted by the added plant pomace. The produced samples can be considered to have a high biodegradability rate. The results of our experimentally produced coatings indicate their possible application on a commercial scale.
Geographical and botanical origin of honeys can be characterized on the basis of physico-chemical composition, sensory properties and on the basis of melissopalynological analysis. No comprehensive description of the characteristics of Czech honey has been published so far. This study provides insights that are important for correct classification. The study analysed 317 samples of authentic honey from randomly selected localities. Due to the diversity of the landscape, the typical honey of the region is blend honey with a predominance of blossom honey. According to the pollen profile and electric conductivity, the honeys were sorted into the following: Brassica honey (BH), Floral honey (FH), Fruit tree honey (PH), Honeydew (HD), Lime tree honey (LH), Robinia pseudoacacia honey (RH), and Trifolium honey (TH). Physico-chemical properties, including higher carbohydrates, were determined for the honeys and their pollen profiles were examined. The physico-chemical properties and pollen profile are partially in compliance with the description of European monofloral honeys, except for RH and TH. Although they had the highest proportion of acacia pollen, amounting to >10% of all the Czech honeys, these RH honeys differ from the European standard, so they cannot be considered acacia honey. Further, PH honeys and FH polyfloral honeys were described. Most honeys contained a significant proportion of rapeseed pollen, which is one of the common agricultural crops grown in the Czech Republic. All the analysed honeys met the parameters defined by the legislation. Due to direct on-site sampling, honeys were characterized by a low 5-(hydroxymethyl)furfural (HMF) content (3.0 mg/kg) and high diastase activity (24.4 DN). Honeydew honeys had the highest proportion of higher carbohydrates, primarily of Melezitose (4.8 g/100 g) and Trehalose (1.3 g/100 g). The presence of higher carbohydrates was also confirmed in LH for Maltose (4.6 g/100 g) and Turanose (2.4 g/100 g).
The study aimed to verify whether the addition of selected herbs and spices will affect the content of polyphenols in biscuits and their antioxidant capacity, as well as what impact it will have on their sensory properties and attractiveness to consumers. Ground cloves, cinnamon, mint, and grape flour were added to the biscuits in concentrations of 1.0, 3.0, 5.0, and 10.0%. The total content of polyphenols in spices and biscuit samples was determined using the Folin–Ciocalteau solution and, subsequently, the antioxidant capacity was measured by FRAP (ferric ion reducing antioxidant power) and DPPH (2,2-diphenyl-1-picrylhydrazyl inhibition). Polyphenols were transferred through spices and herbs into the biscuits in all samples and thus their antioxidant capacity was increased. The antioxidant capacity of the control sample measured by the DPPH method was 15.41%, and by the FRAP method 1.02 μmol Trolox/g. There was an increase in antioxidant capacity in all samples with the addition of spices and herbs. The highest increase was recorded in the sample with cloves, namely with the addition of 10% of cloves there was an increase measured by the DPPH method to 92.6% and by the FRAP method to 208.42 μmol Trolox/g. This also corresponds to the measured TPC (Total Polyphenol Content) in the pure clove, which was 219.09 mg GAE/g, and in the samples where the content gradually grew up to 4.51 mg GAE/g in the sample with the addition of 10%, while the polyphenol content of the control sample was 0.2 mg GAE/g. For other parameters, changes were also observed, depending on the addition of spices/herbs. There was a reduction in both texture parameters, hardness and fracturability, depending on the addition of spices/herbs, which was confirmed by both instrumental measurements and sensory analysis. Colour measurements clearly separated the control from the fortified samples, thus confirming the colour changes. The addition of grape flour shows the smallest difference from the control when the overall impression does not change with the addition. In terms of the combination of increased antioxidant capacity and overall consumer acceptability, the addition of cloves at a concentration of 3.0% appears to be the best option.
The global population’s increasing demand for sustainable and nutritious food sources has led to the exploration of alternative approaches in livestock production. Edible insects have emerged as a promising solution due to their nutritional composition, including high protein content, balanced fats, minerals, vitamins, and bioactive peptides. Biofermentation offers a viable method to enhance the nutritional value of insect feed. This study aimed to investigate the effects of feeding biofermented feeds derived from less valuable raw materials on the yield and nutritional composition of Zophobas morio larvae. The focus was on assessing fat quality, omega-3 and omega-6 fatty acids, and bioactive compounds and monitoring the larvae’s weight and length increases. Three feed types were tested: wheat bran (control), fermented wheat bran, and a mixture of fermented corn and flaxseed in a five-week period. The findings demonstrated a noteworthy (p < 0.05) elevation in polyunsaturated fatty acids, such as gamma-linolenic acid, alpha-linolenic acid, and eicosapentaenoic acid in Zophobas morio larvae fed with biofermented corn and flaxseed pomace, both pre- and postculinary treatment, as compared to the control group. The study also showed increased chelation of Cu2+ (p < 0.05) and Fe2+ (p < 0.05) between native and roasted insects in the samples without in vitro digestion, as well as increased Cyclooxygenase-1 activity (p < 0.05), indicating improved bioavailability. Additionally, culinary processing led to a reduction in polyphenol content (p < 0.05), antioxidant activity (p > 0.05) except DPPH, and peptide concentration (p < 0.05) in the samples without in vitro digestion.