Papers by Dasha Mihaylova
DOAJ (DOAJ: Directory of Open Access Journals), Mar 1, 2015
Storage and its effect on the antioxidant capacity of dried Bulgarian Chrysanthemum balsamita L.
international food research journal, 2015
Nowadays, medicinal plants used in folk medicine are being increasingly studied and used on pharm... more Nowadays, medicinal plants used in folk medicine are being increasingly studied and used on pharmaceutical, food and nutraceutical fields. Yarrow (Achillea millefolium L.) is widely used in both folk and official medicine. Therefore, in the present paper different extracts of yarrow-inflorescences and upper leaves were investigated for their total polyphenolic content and antioxidant activity using several reliable assays, namely DPPH-, ABTS-, FRAP-and CUPRAC assays. The phytochemical profile of the extracts was assessed by RP-HPLC methods as well in order to evaluate the influence of the single constituents. The total polyphenolic content of the extracts was established to be in range 2.74 ± 0.01 and 7.92 ± 0.09 mg GAE/g dw. Among the four applied techniques for extraction the decoction seems to be still the most effective ones. However, the results revealed that the extracts of the Achillea millefolium could be used as easily accessible source of natural antioxidants, but also as a possible food supplement or in pharmaceutical industry.
Foods, May 27, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
international food research journal, 2015
The antioxidant activities of nine Bulgarian plants have been investigated, in the light of recen... more The antioxidant activities of nine Bulgarian plants have been investigated, in the light of recent scientific developments, throughout the world due to their potent pharmacological activities and food viability. In the present study, the possible radical scavenging activity of Clinopodium vulgare L., Cotinus coggygria Scop., Matricaria chamomilla L., Melissa officinalis L., Mentha peperita L., Origanum vulgare L., Salvia officinalis L., Sideritis scardica Griseb. and Thymus vulgaris L. was investigated using different antioxidant methodologies: radical scavenging activity by DPPH and ABTS radicals and reducing power. The extracts have been performed of the dried powered samples using heat-reflux extraction with 96 % ethanol and methanol, respectively. The total polyphenol content of the extracts was investigated as well. The experiments conducted revealed that the investigated plant species are potential sources of polyphenolic compounds and antioxidant activity.
Asian Journal of Pharmaceutical and Clinical Research, Mar 1, 2018
Objective: As old as humankind itself, plants have been used as a source of flavor, food preserva... more Objective: As old as humankind itself, plants have been used as a source of flavor, food preservatives, natural remedies, and ailments. As a part of human culture, medicinal plants are recognized for their healing properties, and the plant knowledge has successfully been transferred from generations to present days. Since natural ingredients enhance safety, medicinal plants' significance is constantly gaining interest because of the therapeutic phytochemicals that they contain. Methods and Results: The paper offers summarized information about the collection, storage, and extraction practices used in Bulgaria. A brief information regarding the distribution of the medicinal plants of the Bulgarian dendroflora is provided along with a review of the biological activities possessed. The various applications in the traditional and folk medicine are presented. Conclusion: Sustainable usage of medicinal plants plays a crucial to their conservation and increased healing potency. Thus, this paper reviews and emphasizes on the optimal collection, harvesting, and extracting approaches of medicinal plants.
Antioxidants
Enzymatic browning could negatively affect the sensory and nutritional properties of eggplants po... more Enzymatic browning could negatively affect the sensory and nutritional properties of eggplants post-harvest. Polyphenols, polyphenol oxidase (PPO), and reactive oxygen species (ROS) are three material conditions involved in enzymatic browning. This paper seeks to evaluate the effect of fertilization techniques and grafting on the activity of PPO and colorimetric parameters in cultivated eggplants. Fertilization alone significantly increased the PPO activity in all eggplant fleshes (p ≤ 0.05), whereas the grafting technique combined with fertilization decreased the PPO activity in most of the samples significantly (p ≤ 0.05). Moreover, there was a significant positive correlation between the PPO activity and the a* values of the eggplants. The a* values in grafted eggplants were significantly different from each other (p ≤ 0.05), showing that grafting the fertilized eggplants could be effective in controlling the enzymatic browning. The eggplant slices exposed to air for 60 min at ro...
Trakia Journal of Sciences
Nowadays, a modern trend of the animal husbandry is to increase the reproductive potential of liv... more Nowadays, a modern trend of the animal husbandry is to increase the reproductive potential of livestock and poultry. There is a large interest worldwide in discovering new and safe non-hormonal biologically active substances obtained from natural sources, which could substitute the synthetic hormones. The positive influence on reproduction in livestock of the biologically active substances of natural origin such as isoflavones, carotenoids, minerals, phytohormones, PUFAs, etc. represent a potential alternative. These substances are derived from various plant sources and micro and macro algae as well. In addition, those substances could provoke positive changes in animal reproduction practices, corresponding to the modern EU requirements for quality and safe for the human health nutrients. The present mini-review summarizes the known in respect of the trend of substitution of the hormonal ones and outlines the potential non-hormonal additives in livestock husbandry.
Molecules
To find the most optimal green valorization process of food by-products, sugar beet (Beta vulgari... more To find the most optimal green valorization process of food by-products, sugar beet (Beta vulgaris L.) leaves (SBLs) were freeze-dried and ground with/without liquid nitrogen (LN), as a simple sample pretreatment method, before ultrasound-assisted extraction (UAE) of polyphenols. First, the water activity, proximate composition, amino acid (AA) and fatty acid (FA) profiles, and polyphenol oxidase (PPO) activity of dried and fresh SBLs were evaluated. Then, conventional extraction (CE) and UAE of polyphenols from SBLs using water/EtOH:water 14:6 (v/v) as extracting solvents were performed to determine the individual and combined effects of the sample preparation method and UAE. In all the freeze-dried samples, the specific activity of PPO decreased significantly (p ≤ 0.05). Freeze-drying significantly increased (p ≤ 0.05) the fiber and essential FA contents of SBLs. The FA profile of SBLs revealed that they are rich sources of oleic, linoleic, and α-linolenic acids. Although freeze-d...
Food Science and Applied Biotechnology
This study is focused on the valorization of sugar beet leaves (Beta vulgaris L.), a prominent by... more This study is focused on the valorization of sugar beet leaves (Beta vulgaris L.), a prominent by-product wasted during the process of sugar. For doing so, Ultrasound-Assisted Extraction (UAE), Pressurized Liquid Extraction (PLE), and Maceration Extraction (ME) methods were compared by evaluating the extraction yield, Total Phenolic Compounds (TPC), Total Flavonoid Content (TFC), individual phenolic profile, and antioxidant activity (e.g., DPPH, FRAP, and ABTS). Ethanol and water (70% V/V) were employed as extracting solvents. The TPC for UAE and PLE methods was 4.90±0.083 and 6.46±0.33 (mg GAE/mL), respectively, differing significantly (P<0.05) from each other. Moreover, the TFC in the PLE method was the highest with 1.45±0.06 mg QE/mL (P<0.05). The antioxidant activity of extracts was significantly different as the PLE method yielded the highest quantities. Benzoic acid was present only in the PLE extracts, while PLE and ME methods recovered the highest quantity of syringic ...
Food and Bioprocess Technology
The concept of functional foods is gaining more importance due to its role in maintaining a healt... more The concept of functional foods is gaining more importance due to its role in maintaining a healthy status and preventing some metabolic diseases. The control of diabetes, in particular type-2 (T2DM), could be considered a big challenge since it involves other factors such as eating habits. From the pharmacological point of view, inhibiting digestive enzymes, such as α-amylase and α-glucosidase, is one of the mechanisms mainly used by synthetic drugs to control this disease; however, several side effects are described. For that reason, using bioactive compounds may appear as an alternative without presenting the complications synthetic drugs available on the market have. The winemaking industry generates tons of waste annually, and grape pomace (GP) is the most important. GP is recognized for its nutritional value and as a source of bioactive compounds that are helpful for human health. This review highlights the importance of GP as a possible source of α-amylase and α-glucosidase i...
IOP Conference Series: Materials Science and Engineering, 2021
Edible flowers are considered as a valuable source of bioactive compounds and are used as food an... more Edible flowers are considered as a valuable source of bioactive compounds and are used as food and medicine with growing interest. Microwave extraction technique was employed as a green approach to obtain water extracts from seven edible flowers including Viola tricolor L., Cucurbita pepo L., Sambucus nigra L., Calendula officinalis L., Hibiscus rosa-sinensis L., Rosa damascena Mill. and Allium ursinum L. They were characterized in terms of total content of phenolics and flavonoids, as well as antioxidant potential. The total phenolic content in the edible flower’s extracts ranged between 12.08 ± 0.09 and 72.66 ± 0.60 mg gallic acid equivalent (GAE)/g dw and the total flavonoid content was established to vary between 2.36 ± 0.09 and 25.91 ± 0.09 mg quercetin equivalents (QE)/g dw. The highest values were reported in the extracts of Viola tricolor and Rosa damascena. Moreover, the same extracts displayed the highest antioxidant activity evaluated by six in vitro assays. The lowest ac...
European Food Research and Technology, 2021
Grape pomace is a winery by-product that is more and more valorized as a source of healthy bioact... more Grape pomace is a winery by-product that is more and more valorized as a source of healthy bioactive molecules such as polyphenols. In addition, it can be used to produce some alcoholic beverages, such as grappa , which is a typical distilled Italian alcoholic product. The spent grape pomace after grappa elaboration is mainly considered a food waste. The aim of this study was to reconsider and valorize red and white pomaces obtained after the production of grappa. The total phenolic content of both samples, as well as the antioxidant activity had a decrease after the distillation; however, it was not significant in the case of red pomace. Regarding the phenolic profile, the behavior during the distillation was different, according to the type of pomace. After the grappa production, catechins and epicatechins were the most significant phenolics in white and red pomace, respectively, demonstrating the remaining bioactivity of this by-product, which could be useful within the food industry.
Foods
Higher basidiomycetes are recognized as functional foods due to their bioactive compound content,... more Higher basidiomycetes are recognized as functional foods due to their bioactive compound content, which exerts various beneficial effects on human health, and which have been used as sources for the development of natural medicines and nutraceuticals for centuries. The aim of this study was to evaluate and compare the biological potential of basidiocarp and mycelial biomass produced by submerged cultivation of a new regionally isolated oyster mushroom. The strain was identified with a high percentage of confidence (99.30%) as Pleurotus ostreatus and was deposited in the GenBank under accession number MW 996755. The β-glucan content in the basidiocarp and the obtained mycelial biomass was 31.66% and 12.04%, respectively. Three mycelial biomass and basidiocarp extracts were prepared, and the highest total polyphenol content (5.68 ± 0.15 mg GAE/g DW and 3.20 ± 0.04 mg GAE/g DW) was found in the water extract for both the fruiting body and the mycelium biomass. The in vitro antioxidant ...
Foods
Bifidobacterium is a predominant and important genus in the bacterial population of the human gut... more Bifidobacterium is a predominant and important genus in the bacterial population of the human gut microbiota. Despite the increasing number of studies on the beneficial functionality of bifidobacteria for human health, knowledge about their antioxidant potential is still insufficient. Several in vivo and in vitro studies of Bifidobacterium strains and their cellular components have shown good antioxidant capacity that provided a certain protection of their own and the host’s cells. Our work presents the data of transcriptomic, proteomic, and metabolomic analyses of the growing and stationary culture of the probiotic strain B. longum subsp. longum GT15 after exposure to hydrogen peroxide for 2 h and oxygen for 2 and 4 h. The results of the analysis of the sequenced genome of B. longum GT15 showed the presence of 16 gene-encoding proteins with known antioxidant functions. The results of the full transcriptomic analysis demonstrated a more than two-fold increase of levels of transcript...
Horticulturae
The natural products of the plant kingdom, both terrestrial and marine, have been widely explored... more The natural products of the plant kingdom, both terrestrial and marine, have been widely explored [...]
Plants
Chlorophylls are a group of naturally occurring pigments that are responsible for the green color... more Chlorophylls are a group of naturally occurring pigments that are responsible for the green color in plants. This pigment group could have numerous health benefits due to its high antioxidant activity, including anti-inflammatory, anti-cancer, and anti-obesity properties. Many food by-products contain a high level of chlorophyll content. These by-products are discarded and considered environmental pollutants if not used as a source of bioactive compounds. The recovery of chlorophylls from food by-products is an interesting approach for increasing the sustainability of food production. This paper provides insight into the properties of chlorophylls and the effect of different treatments on their stability, and then reviews the latest research on the extraction of chlorophylls from a sustainable perspective.
Plants
A fruit’s aroma profile, composed of a complex mixture of volatile organic compounds, is among th... more A fruit’s aroma profile, composed of a complex mixture of volatile organic compounds, is among the core attributes related to the overall taste and consumer preference. Prunus persica L. is a preferred summer fruit with a distinct, favorable olfactory characteristic. The volatile compositions of both peach fruits and fruit pulps from eight peach cultivars (four native and four introduced) was investigated to compare their composition and assess flavor-contributing compounds. In total, 65 compounds were profiled after a HS-SPME-GC-MS analysis: 16 esters, 14 aldehydes, 5 alcohols, 7 hydrocarbons, 7 ketones, 8 acids, and 8 terpenes. The most common compounds were esters, acids, and aldehydes. Although the same compounds were identified in both fruit and pulp, their %TIC (total ion current) differed in favor of the whole fruit. Following the metabolic profiling of the whole fruit and fruit pulp, a total of 44 compounds were identified from the studied varieties. Among them, amino acids,...
Applied Sciences
Dietary proteins are no longer just nutritional ingredients in our food. During hydrolysis, some ... more Dietary proteins are no longer just nutritional ingredients in our food. During hydrolysis, some of the released peptides may possess properties that favor the health of the human body. In our study enzymatic hydrolysis of lupin proteins was performed using papain. Three enzyme-to-substrate ratios were set for three different duration times. The SDS-PAGE of the samples was performed. Each hydrolysate was studied for the degree of hydrolysis (DH), acetylcholinesterase (AChE) inhibitory, antimicrobial, and antioxidant activities (AOA, according to four spectrophotometric methods). The DH varied from 9.06 ± 0.20 to 27.97 ± 0.37%. According to the results, the best AOA was measured by the ABTS method (from 0.76 ± 0.03 to 1.15 ± 0.46 M TE/100 g protein). All the hydrolysates displayed AChE inhibitory activity (IC50), which varied between 155.58 ± 1.87 and 199.63 ± 0.41 mg/g protein. To the best of our knowledge, this is the first report of the acetylcholinesterase inhibitory activity of ...
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Papers by Dasha Mihaylova