By-products of winemaking industry as source of bioactive compounds: characterisation and possibility of its applications in food industry

U okviru ove doktorske disertacije su okarakterisana fenolna jedinjenja pokožice i semenke izdvojene iz nefermentisane komine internacionalnih i autohtonih sorti grožđa, kao i fermentisane komine vinske sorte Prokupac. Dijetna vlakna, šećeri i masne kiseline u semenkama komine grožđa su dodatno okarakterisani. Odabrani ekstrakti fenolnih jedinjenja su korišćeni u formulaciji funkcionalnih aditiva na bazi proteina kozijeg mleka i kozijih jogurata dobijenih korišćenjem starter kultura i selekcionisanog Lactobacillus plantarum soja. Utvrđen je efekat matriksa hrane (meso/žitarice, proteini kozijeg mleka, dijetna vlakna (inulin), proteini mleka/dijetna vlakna), na biodostupnost fenolnih jedinjenja iz pokožice i semenki grožđa nakon in vitro digestije. Za postizanje ovih ciljeva koriščene su: spektrofotometrijske, kuplovane hromatografske, elektroforetske i DNK-zasnovane tehnike, zajedno sa spektroskopskim, fizičko-hemijskim i biohemijskim analizama. Brašna semenki izdvojenih iz nefermentisane komine dobar su izvor nerastvornih/ukupnih dijetnih vlakana, zaostalih šećera (glukoza i fruktoza) i nutritivno vrednih masnih kiselina (linolne i oleinske kiseline). Procijanidini i katehin su dominantna fenolna jedinjenja u semenkama, dok su u pokožicama najzastupljeniji flavonoli, kao i malvidin i peonidin derivati iz klase antocijana. Liofilizacija fermentisane komine Prokupca i njenih konstituenata ima neznatan uticaj na sadržaj dominatnih fenolnih jednjenja koja su ispoljila dobra antioksidativna svojstva. Ekstrakt pokožice pokazao je ćelijsku antioksidativnu aktivnost na humanim ćelijama kolorektalnog adenokarcinoma, dok se ekstrakt liofilisane peteljke pokazao kao dobar izvor stilbenoida. Dodatkom ekstrakta semenki grožđa i inulin/ekstrakt praha u termički tretirano kozije mleko utvrđeno je prisustvo polifenol-protein interakcija, prvenstveno procijanidina sa serum protein/kazein kompleksima. Dobijeni funkcionalni aditivi su pokazali dobra antioksidativna svojstva, dok su 0,1% rastvori pokazali dobra emulgujuća i loša peniva svojstva. Predloženi su modeli distribucije fenolnih jedinjenja između serum i micelarne faze kozijeg mleka, kao i distribucije kazeinskih micela na međufazama ulje/voda i vazduh/voda u emulzijama i penama formiranim od odabranih funkcionalnih aditiva. Jogurt od kozijeg mleka sa dodatim ekstraktom semenki grožđa, fermentisan starter kulturom i L.plantarumom, je pokazao dobra teksturna i senzorna svojstva. Ovaj liofilisani jogurt je pokazao bolja antioksidativna i emulgujuća svojstva u poređenju sa drugim liofilisanim jogurtima. Svi liofilisani jogurti, koji su fermentisani sa L.plantarum-om, pokazali su visoku vijabilnost ćelija (>108 CFU/g SM). Biodostupnost fenolnih jedinjenja iz pokožice i semenki grožđa nakon in vitro digestije bila je različita i zavisna od sastava matriksa, i kretala se od 6,03% za matriks kozije mleko/inulin do 50.9% za matriks meso/žitarice, dok su proteini rastvorljivih frakcija digestovanih funkcionalnih aditiva bili potpuno hidrolizovani nakon in vitro gastrointestinalne digestije. Digestovani funkcionalni aditivi pokazali su smanjena (osim kod meso/žitarice matriksa) antioksidativna svojstva u odnosu na nedigestovane uzorke, što je bilo u korelaciji sa smanjenom biodostupnoću fenolnih jedinjenja. Na osnovu dobijenih rezultat može se zaključiti da komina vinske sorte Prokupac i njeni konstituenati, mogu biti jeftin izvor fenolnih jedinjenja pogodnih za razvoj funkcionalnih prehrambenih proizvoda, dok njeno korišćenje istovremeneo omogućava zaštitu životne sredine.The aim of this doctoral dissertation was characterisation of phenolic compounds of skins and seeds separated from non-fermented pomace of international and indigenous grape varieties, as well as phenolic profiles of fermented pomace of the Prokupac grape variety. Dietary fiber, sugars, and fatty acids from grape pomace seed extracts were also characterized. Selected phenolic extracts were used in the formulation of functional additives based on goat milk protein and goat yogurts produced with the utilisation of starter culture and selected Lactobacillus plantarum strain. The effect of food matrices (meat/cereal, goat's milk protein, dietary fiber (inulin), goat’s milk protein/dietary fiber) on the bioaccessibility of phenolic compounds from skin and grape seeds after in vitro digestion was evaluated. Spectrophotometric, coupled chromatographic, electrophoretic, and DNA-based techniques together with spectroscopy, physicochemical and biochemical analyses were used to achieve these aims. Grape seed flours of non-fermented pomaces are a good source of insoluble/total dietary fiber, residual sugars (glucose and fructose), and nutritionally valuable fatty acids (linoleic and oleic acids). Procyanidins and catechin were dominant in the seeds, while flavonols, malvidin and peonidin derivatives were the most common phenolic compounds in the skins. Lyophilization of fermented Prokupac pomace and its constituents has a slight effect on the dominant phenolic compounds that showed good antioxidant properties. The skin extract exerted cellular antioxidant activity on adenocarcinoma cells, while extract of lyophilized pomace stems showed as a good source of stilbenoids. After the addition of seed extract and inulin/extract powder to thermally treated goat milk, the presence of polyphenol-protein interactions were recorded, primarily procyanidin with serum protein/caseins (WP/CN) complex. Furthermore, obtained functional additives showed good antioxidant properties, whereas 0.1% solutions showed good emulsifying properties but poor foaming techno-functional properties. Models of phenolic compounds distribution between serum and micellar phases in thermally treated goat milk, as well as the distribution of casein micelles at the oil/water and air/water interfaces in emulsions and foams of selected functional additives were proposed. Goat yogurt with seed extract fermented with starter culture and L. plantarum showed good textural and sensory properties. This lyophilized yogurt showed better antioxidant and emulsifying properties compared to other lyophilised yoghurts. All lyophilized yoghurts, fermented with L.plantarum, showed high cell viability (>108 CFU/g SM). The bioaccessibility of individual phenolic compounds from grape skins and seeds were different and dependent on the composition of the food matrix. The bioaccessibility ranged from 6.03% for goat milk/inulin matrix to 50.9% for meat/cereals matrix, whereas soluble protein fractions of digested functional additives were completely hydrolyzed after in vitro gastrointestinal digestion. The digested samples showed reduced (except for meat/cereal matrix) antioxidant properties compared to their undigested samples, which were related to the reduced bioaccessibility of phenolic compounds. Based on the obtained results it can be concluded that grape pomace of the Prokupac variety can be a cheap source of phenolic compounds suitable for the development of functional food products, while its utilisation allows, at the same time, enviroment protection

Content of free polyphenols and flavonoids in organic and conventionally produced buckwheat seed

Buchwheat (Fagopyrum esculentum) is an annual alternative cereal from the Polygonaceae family gaining high attention among consumer in past decade. It is mostly grown for grain, which is processed into flour and numerous food products. Buckwheat is a very important source of phytochemicals, specially phenolics which have the many human health benefits. Numerous researches have proved that phenolics participate in the prevention of many diseases such as neurodegenerative diseases, cancer, osteoporosis, cardiovascular diseases system, diabetes, etc. In the group of cereals and alternative cereals, buckwheat stands out as a high phenolic source grain having high antioxidant capacity. The aim of this work was to determine the content of the most important antioxidants – total phenolics and flavonoids in buckwheat seed produced in organic and conventional agricultural production during 2016. Content of free (extractable) phenolics and flavonoids was determined using standard spectrophotometric methods with Folin-Ciocalteu reagent and aluminum chloride, respectively. Content of free phenolics was expressed as mg of ferulic acid equivalents (FAE) per kg of dry sample weight (DW) while free flavonoids content was expressed as mg of quercetin equivalents (QE) per kg DW. Content of free phenolics ranged from 6505.7 (organic seed) to 6656.1 (conventional seed) mg FAE/kg DW. Content of free flavonoids was 879.19 mg QE/kg DW in conventional seed, while organic buckwheat seed exhibited significantly higher content- 1094.7 mg QE/kg DW. The obtained results indicated that organic buckwheat seeds are a better source of total phenolics and flavonoids compared to conventional seeds

Health Benefits and Applications of Goji Berries in Functional Food Products Development: A Review

Goji berries have long been used for their nutritional value and medicinal purposes in Asian countries. In the last two decades, goji berries have become popular around the world and are consumed as a functional food due to wide-range bioactive compounds with health-promoting properties. In addition, they are gaining increased research attention as a source of functional ingredients with potential industrial applications. This review focuses on the antioxidant properties of goji berries, scientific evidence on their health effects based on human interventional studies, safety concerns, goji berry processing technologies, and applications of goji berry-based ingredients in developing functional food products

Nutritional behavior and motives of college students for the choice of traditional food in the Republic of Serbia

The aim of this study was to investigate the eating behavior of college students and the reasons for consuming traditional food and to compare the motives for choosing traditional food with the research conducted in 6 European countries. This research was conducted using anonymous online questionnaires. The majority of surveyed students are physically active (75%) and live with their families (57.0%), which can have a positive impact on their diet and a lower level of consumption of "fast-food" (17.5%). Respondents have bad habits in terms of consuming cigarettes (65.0%), alcohol (73.0%) and energy drinks (75.0%). Most students consume all regular meals (73.0%). Based on the Body Mass Index (BMI) of respondents, they belong to the categories: underweight (12%), normal weight (34%), pre-weight (17%), obese (37%); however, 55.0% believed to have "ideal weight". The reasons for choose particular food are: it is not genetically modified, it tastes good, it is nutritious, it makes them happy, it was produced/packaged in an environmentally friendly and ethical way, while the price of food is not important. Connection with family (81%) and food being tasty (54%) are the main reasons for consuming traditional food. When buying traditional food, respondents (59%) generally do not check the declaration on the product. These results indicate the need to educate students about the harmfulness of cigarettes, alcoholic and energy drinks, the importance of BMI and declaration on the product. Comparing obtained results with the results in 6 European countries it can be noticed that the answers of the respondents in Serbia were the most similar to those obtained in Poland

THE EFFECT OF PARTIAL PROTEOLYSIS ON TECHNO - FUNCTIONAL AND ANTIOXIDANT PROPERTIES OF MODIFIED SOY PROTEIN ISOLATES

The partial enzymatic hydrolysis is effective and safe method which can be used to improve nutritive, techno-functional and functional properties of soy protein products. This method is affected by numerous factors. The objective of this work was to examine the effect of partial proteolysis on emulsifying and foaming properties of soy protein isolate. Also, the effect of proteolysis on ABTS-radical scavenging activity and iron (III) chelating ability was followed. Spray-dried soy protein isolate was prepared by isoelectric precipitation and modified using three different commercial proteases, Alcalase, Flavourzyme, and Papain. Initial isolate was hydrolyzed for 30, 60 and 90 minutes. Proteolysis was followed by the change of degree of hydrolysis (DH) and by native-PAGE, SDS-PAGE under reducing and non-reducing conditions. The effect of proteolysis on emulsifying properties was followed using emulsion stability index (ESI) and emulsion activity index (EAI). Also, foaming capacity and stability of foams formed using modified isolates were determined. Emulsifying and foaming properties was measured at pH 3, 5 and 7. Modified isolates were characterized with different DH values which were in the range of 11.75±0.08 (30 min, Papain) - 43.30±0.15 (Alcalase, 90 min). Limited proteolysis differently affected emulsifying properties of soy protein isolate. All modified isolates had improved emulsion stability at all investigated pH value whereas their ability to form emulsion was slightly lower or equal to initial isolate but in the range of commercial isolate used as standard. The highest stability had samples modified 30 min using Flavourzyme (366.94±48.85 min). Contrary, limited hydrolysis improved foaming capacity, but these foams were extremely unstable. The used enzymes differently affected the antioxidant properties of soy isolate. Only Alcalase improved radical scavenging activity of the initial isolate whereas the reducing power of all the investigated hydrolysates was lower than that of the initial isolate. Alcalase and Papain improved the ability of isolate to chelate iron (II) ions, whereas Flavourzyme-modified isolates had reduced iron (II) chelating ability. The initial IC50 of soy isolate was improved by 31.55-43.87% (Alcalase-modified) and by 21.08-60.40% (Papain-modified)

Selected bioactive compounds content of cinnamon spice

Cinnamon spice is obtained by peeling the inner bark of an evergreen tree Cinnamomum zeylanicum (fam. Lauraceae), native to Sri Lanka. It is one of the earliest known spices on the Asian continent. Today, it is highly valued and widely used all around the world, as a whole (bark sticks), ground spice or essential oil. Cinnamon has a long tradition of use in cooking (as flavoring agent), aromatherapy (as fragrant agent), traditional medicine (for treatment toothache, dental problems, bad breath, diabetes, rheumatism), and is also recognized in official medicine (show antioxidant, antidiabetic, antimicrobial, anti-inflammatory activities). The biological activity of cinnamon is attributed to a number of bioactive compounds, and as the most important stood out cinnamaldehyde and trans-cinnamaldehyde (Cin). In this study, dry, ground cinnamon was analysed to determine the content of: total phenolics (TPC), total flavonoids (TFC), total hydroxycinnamic acid derivatives (HCAs) and total carotenoids (TCC). Bioactive compounds were extracted by solvent extraction (SE) and ultrasound assisted extraction (USE) in 80% acetone and warm water (50 °C). The content of bioactive compounds were determined spectrophotometrically. The TPC in acetone extracts prepared by UAE was the highest (29.83 ± 0.02 mg GAE/g of DW), but did not show a significant difference in comparison to TPC achieved in acetone extract obtained by SE (29.79 ± 0.11 mg GAE/g of DW). The highest TFC (1.41 ± 0.17 mg CE/g of DW) and HCAs (14.59 ± 0.79 mg CGAE/g of DW) were observed in acetone extract prepared by SE, while the highest TCC (277.10 ± 4.82 μg/g) was acquired in acetone extract prepared by UAE. Also, the content of tested bioactive compounds of cinnamon in water extracts was higher compared to some spices described in recent studies, which places cinnamon as a good source of bioactive compounds with potential health benefits

Content of phytosterols in organic and conventional produced maize and spelt seed

Phytosterols or plant sterols belong to a wide group of steroids with great physiological importance. Phytosterols are found abundant in vegetable oils and maize kernel oil. However they are also beneficial for human health. The content of phytosterols in plants is especially important because they can help to decrease cholesterol level in the intestinal tract. Numerous studies indicate that organically produced plants have a higher amount of numerous phytochemicals compared to conventional. The aim of this study was to determine the potential differences in the content of phytosterols in organically and conventionally produced maize and spelt seeds. Samples were obtained during 2016 season from experimental field of Maize Research Institute (Zemun Polje, Serbia). In order to quantify phytosterols extracts in chloroform were prepared and resulting products of the Lieberman-Burchard reaction was obtained as green colored. The absorbance of obtained green complexes was determined on a spectrophotometer at 640 nm. Results are expressed in mg kg-1 of dry sample weight (DW). According to the obtained results, organic maize seed contained double the amount of phytosterols compared to (324.97 mg kg-1 DW) conventional sample (147.02 mg kg-1 DW). Spelt seeds contained a significantly lower amount of phytosterols: conventional seed contained 288.96 mg kg-1 DW, while organic seed contained only 98.3 mg kg-1 DW. The obtained results indicated that organic maize seeds are a better source of phytosterols copared to spelt seeds

Antioxidant Properties of Freshly Collected Leaves of Diplotaxis tenuifolia (L.) DC

Diplotaxis tenuifolia (L.) DC, recognized by its common name of wild rocket, has a notable role within the Brassicaceae family. The leaves of this plant offer a unique flavor that enhances culinary preparations, alongside their influence on improvement in overall human well-being due to their nutrient and bioactive compound content. Wild rocket possesses a wide range of antioxidants, incorporating vitamins such as C and E, along with carotenoids, glucosinolates, and flavonoids. The objective of this study was to assess the antioxidant properties of the fresh leaves from three wild rocket hybrids: Marte F1, Venere F1, and T&T F1. Using an 80% acetone solution as the solvent, powdered plant material was subjected to a 3-h extraction period at a ratio of 1:10 (plant material/solvent). After the extraction process, the antioxidant properties of the extracts were assessed spectrophotometrically using four distinct assays: DPPH⦁, ferric reducing power (FRP), in vitro phosphomolybdenum total antioxidant capacity (TAC), and cupric reducing antioxidant capacity (CUPRAC). Phytochemical analyses disclosed a variation in the quencher assay results among hybrids, ranging from 5.42 to 6.19 μmol Trolox/g. Nevertheless, the statistical analysis indicated a lack of statistically significant differences among the hybrids within this specific quencher assay. Similarly, no statistically significant differences were found among the samples in relation to the TAC results. The T&T hybrid achieved the highest results in both the FRP and the CUPRAC assays (2.79 mg/g AAE and 17.73 mg/g AAE respectively). Notably, there were no statistical differences observed between the T&T and Venere hybrids. However, both the T&T and Venere hybrids exhibited statistically significant differences when compared to the Marte hybrid. The overall results showed variations among the chosen hybrids regarding their antioxidant properties, while indicating the potential of fertilization in the enhancement of the bioactive compound profile and biological activity

APPLICATION OF RAMAN SPECTROSCOPY FOR THE CHARACTERISATION OF MILK AND MILK-PHENOLICS POWDERS

The current trend of food innovations is a development of different milk products enriched with phenolic compounds extracted from food by-products. This represents a promising strategy for food waste recovery and to enhance the beneficial health effects of milk-based functional foods. As one of the promising food ingredients can be skim goat milk enriched with grape pomace seed extract due to improved antioxidant properties of goat milk proteins. So, the aim of this study was the Raman analysis of spray-dried powders of skim goat milk, heated goat milk, and heated goat milk enriched with different concentrations of grape pomace seed extract. The whole statistical procedure (pre-processing and PCA) of Raman spectra was performed independently at Amide I (1700-1600 cm-1), Amide II (1600-1500cm-1), and Amide III (1500-1200cm-1) regions. Raman spectra analysis of amide I and II regions showed a separation between heated and unheated milk due to the loadings for 1650-1653 (α-helix), 1661-1663, 1675, and 1686 cm-1 (turn). Furthermore, in the amide I region, the differences between milk enriched with different concentrations of grape pomace seed extract can be observed due to loadings for wavenumbers in the 1612-1644 cm-1 region. These differences can be related to the changes in the parallel and antiparallel β-sheet structures, differences in the vibrations of the amino acid residues of tyrosine, tryptophan, and phenylalanine and the vibrations of ν(C=C) bonds from the aromatic ring of free flavan-3-ols (catechin, epicatechin, epigallocatechin). For the amide III region, the applied heat treatment and interactions of proteins with phenolic compounds distinguished samples in loadings for wavenumber in 1236-1257 and 1267-1304 cm-1 ranges. These differences can be related to the changes in the α-helix and random coil structures. It can be concluded that PCA separation of analyzed powders in amide I and III regions of Raman spectra caused by the applied thermal treatment, presence of free phenolic compounds, and protein-phenolics interactions, can be used for the characterization of milk and milk-phenolics powders

Phytochemical analysis of Cicerbita pancicii (Vis.) Beauverd­the Balkan’s endemic plant

The Balkan Peninsula is characterized by the great biodiversity, and it is native to extensive number of plant families and species. Moreover, some plants are endemic to certain region such as Cicerbita pancicii (Vis.) Beauverd (syn. Lactuca pancicii) from the Asteraceae family. This perennial plant can be found in mountainous areas, growing among tall-herb vegetation, as it prefers humid mild limestone slopes along streams [1]. During spring months, C. pancicii develops upright steam with lyrate leaves which are composed of broad terminal lobe and several smaller lateral ones. Pollination is occurring as insect are attracted to the decorative lilac-purple flowers, arranged in capitula. The aim of this study was to perform phytochemical analysis of three distinct plant parts of this endemic species: stem, leaf and inflorescence. For this purpose, plants are collected from Rudinice village, nearby Komarnica canyon in the Montenegro. Furthermore, extraction of plant material was performed in 80% acetone as solvent and content of chlorophyll a and b, as well as total carotenoid (TCC), total phenolic (TPC) and total flavonoid (TFC) content were determined using spectrophotometric methods. The leaves possessed the highest amount of both chlorophylls a (611.52 μg/g d.w.) and b (993.38 μg/g d.w.), whereas the lowest values were registered in steam (113.27 μg/g i.e. 45.92 μg/g d.w.). Moreover, TCC was the most abundant in inflorescence (65.71 μg/g d.w.), while in leaves carotenoids were not detected. Analysis of TPC and TFC exhibited the highest distribution of phenolic and flavonoid compounds in leaves of C. pancicii (12.51 mg/g GAE and 18.19 mg/g CE d.w.), followed by content in inflorescence (8.23 mg/g GAE and 10.42 mg/g CE d.w.). As the result of this study, the dispersal of mentioned bioactive compounds within plant organs has been recognized and determined