Ruta Galoburda

Content of Phenolic Compounds in Various Sea Buckthorn Parts

Abstract All parts of the sea buckthorn (Hippophae rhamnoides L.) plant are considered to contain large amounts of compounds that are believed to have beneficial health effects. Till now, different parts of sea buckthorn plant have been used for the treatment of diseases in traditional medicine in various countries. Nevertheless, sea buckthorn parts would be a good raw material not only for medicinal properties but also for food products with functional properties; therefore, the aim of the research was to determine the concentration of different phenolic compounds and antioxidant activity in various sea buckthorn parts. The study was conducted on parts of female and male sea buckthorn bushes. Phenolic compounds (total phenols, total flavonoids and condensed tannins) and antioxidative activity (ferric reducing antioxidant power (FRAP) free radical scavenging activity (using 2.2-diphenyl-1-picrylhydrazyl, DPPH)) in ethanolic extracts of leaves, shoots, flowers, and berries were determined using various spectrophotometric methods. The study showed that concentration of phenolic compounds differed among parts of sea buckthorn plant and among gender. Leaves of female plants proved to be the most valuable, as they contained the highest total phenol concentration (165.76 mg/g) and antioxidant activity (220.97 mg/g for FRAP and 43.76 mg/g for DPPH), while lowest values were found in young shoots of male plants (84.94 mg/g, 94.24 mg/g and 24.63 mg/g, respectively). The significant differences in chemical composition and biological activity of sea buckthorn leaves, shoots, berries, and buds indicate a need for detailed studies of their extracts, specific fractions and compounds during a whole vegetative season. Abstrakt Rakstā aplūkots fenolsavienojumu saturs dažādās smiltsērkšķu auga daļās un to antioksidatīvā aktivitāte. Kā pētījuma objekts izvēlētas sievišķo un vīrišķo augu lapas, jaunie dzinumi, zaļās ogas, kas ievāktas jūnija vidū, un ziedi, kas ievākti aprīļa beigās. Paraugiem analizēts kopējo fenolu, kopējo flavonoīdu un kondensēto tanīnu saturs, kā arī antioksidatīvā aktivitāte ar FRAP (ferric reducing antioxidantpower) un DPPH (2.2-diphenyl-1 -picrylhydrazyl) metodi. Vērtīgākā auga daļa izrādījās sievišķā auga lapas, kurām konstatēts augstākais kopējo fenolu saturs un antioksidatīvā aktivitāte, lietojot abas metodes, savukārt vismazākie minētie rādītāji bija jaunajiem dzinumiem no vīrišķā auga. Rezultāti norāda uz būtiskām atšķirībām smiltsērkšķu auga daļu ķīmiskajā sastāvā un bioloģiskajā aktivitātē, tādēļ nepieciešami padziļināti pētījumi par ekstraktiem, to frakcijām vai atsevišķiem savienojumiem un to izmaiņām visā veģetācijas sezonā.

Composition of Volatile Compounds of Horseradish Roots (Armoracia rusticana L.) Depending on the Genotype

Abstract Horseradish is a perennial plant with significant antioxidant properties, and it contains about 0.2% to 1.0% of essential oil, mainly sinigrin, sinigrin-derived allylisothiocyanate and diallylsulphide. The aim of the study was to determine composition of volatile compounds of horseradish (A. rusticana L.) roots depending on the genotype. Volatiles from fresh horseradish roots of nine genotypes were extracted using solid phase microextraction with DVB/Car/PDMS fibre and were further analysed using gas chromatography-mass spectrometry. The volatile compounds were identified by comparing their mass spectra with mass spectral libraries (Nist98) and by calculating linear retention indexes and comparing them with the literature data. The studied horseradish genotypes differed both in the quantitative and qualitative content of aroma compounds. Totally 15 volatile compounds were detected, and their highest amount was found in genotype G12B. The main aroma compound of all horseradish samples was allylisothiocyanate, which formed 64-82% of the total identified volatile compounds. The obtained results were compared with those found in the literature. All horseradish samples contained significant amounts of phenylethylisothiocyanate (4-18%) that is formed from glucosinolate - gluconasturtin. The study revealed that genotype has great influence on the content of volatiles in horseradish roots.

Effect of High-Pressure Processing on Microbial Quality of Skimmed Milk

Abstract High pressure processing (HPP) is an alternative to traditional thermal treatment and can be used in the dairy industry for increasing the microbiological safety of milk and for preserving its biologically active substances. HPP effectiveness in providing microbiological quality of product is still under discussion; thus, the aim of the study was to evaluate the effect of HPP technology on microbiological quality of skimmed milk. Raw, pasteurised (78 °C, 15–20 s), HPP treated (250 MPa, 15 min; 400 MPa, 3 min; 400 MPa, 15 min; 550 MPa, 3 min) and skimmed milk, processed by combining pasteurisation and HPP were analysed and compared. The total plate count (LVS ISO 4833-1:2013) and presence of coliforms (LVS EN ISO 16654:2002) were determined in analysed skimmed milk samples. Significant decrease (p < 0.05) of colony forming units (CFU) was observed in samples processed by combining two treatment types: pasteurisation and HPP. The minimum treatment parameters for shelf-life extension of skimmed milk were determined: pressure not less than 400 MPa and holding time at least 15 minutes.

Quality Parameters Of Wheat Bread Enriched With Pumpkin (Cucurbita Moschata) By-Products

Abstract Pumpkin processing into puree, juice, candied fruit and pumpkin seed oil results in large amount of by-products. Pumpkins are rich in carotenes, vitamins, minerals, pectin and dietary fibre. The aim of the current study was to evaluate effect of pumpkin pomace and pumpkin residue powder on wheat bread quality. The total content of carotenes was analyzed by spectrophotometric method. The initial increase of pumpkin residue addition indicated increase in loaf volume, which started to decrease at higher amounts. Sensory evaluation (appearance; surface, crust; porosity; texture, crumb; taste, and flavour) of wheat bread with pumpkin revealed very high consumer acceptance except sample with 50% pomace addition. Total carotene content and colour b* value in wheat bread increased by adding pumpkin by-products. It is recommended to add 5% and 10% of pumpkin powder and no more than 30% of pumpkin pomace (calculated per 100 kg of flour) to dough for production of wheat bread with pumpkin by-product additions.

Nutritional Quality of Triticale (×Triticosecale Wittm.) Grown under Different Cropping Systems

Abstract Triticale (× Triticosecale Wittm.) is mainly used for animal feed, but recent studies have shown its possible beneficial effect for human health. The objective of this study was to investigate the nutritional quality of triticale grown under different cropping systems in Latvia. Two winter triticale varieties, ‘Inarta’ and ‘Ruja’, were cultivated in 2014 and 2015 under conventional and organic cropping systems. Protein, starch, and total dietary fibre were determined using standard methods. Ultrasound assisted extraction was used for isolation of phenolic compounds. Total phenol content (TPC) and radical scavenging activity in extracts were determined spectrophotometrically. Overall, the highest content of protein, TPC and ABTS cation scavenging activity occurred in triticale harvested in 2014, due to favourable weather conditions (warm weather and more precipitation in June–July) for accumulation of these compounds during grain filling. Higher starch content in all studied samples harvested in 2015, as compared to 2014, was explained by higher precipitation in July 2015. The type of cropping system had no significant effect (p > 0.05) on protein and starch content, while TPC, DPPH, and ABTS·+ scavenging activity was influenced by cropping system, depending on variety.

The Effect of Freezing and Hydrocolloids on the Physical Parameters of Strawberry Mass-Based Desserts

Abstract The aim of the study was to evaluate the effect of freezing, thickening and storage on the physical properties of the strawberry desserts made with addition of various hydrocolloids. The strawberry cultivars ‘Polka’, ‘Honeoye’, and ‘Senga Sengana’ harvested in Latvia were used in the study. The strawberries were processed in a blender for obtaining a homogenous mass. The strawberry mass was analyzed fresh and after storage at -18 °C. Both fresh and frozen strawberry mass samples with added gelatine, xanthan gum, and sodium carboxymethyl cellulose were whisked until obtaining dessert. For determination of the optimum hydrocolloid amount, sensory evaluation was done using a five-point hedonic scale. Moisture, soluble solids content, density, and pH of the product were determined. Apparent viscosity was measured using a rotational viscometer DV–III Ultra. Consistency of the dessert during its storage was evaluated using a texture analyser TA.XT.plus. The results of sensory evaluation allow concluding that in order to provide the most acceptable consistency, colour, and taste of strawberry dessert, the optimum quantity of carboxymethyl cellulose and xanthan gum to be added is 0.6% and that of gelatine is 6%. During freezing, the soluble solids content and pH level decreased in the strawberry mass, whereas the addition of hydrocolloids increased these values. The moisture content in strawberry puree, in its turn, as a result of freezing increased under the influence of syneresis, but added hydrocolloids, on the contrary, decreased this influence. Also the viscosity and consistency of the strawberry puree prepared from the researched cultivars decreased under the influence of freezing, whereas the addition of hydrocolloids increased both the values, making the strawberry dessert firmer. The research suggests that strawberry dessert with gelatine had the most pronounced changes during storage, but strawberry dessert with added xanthan gum and carboxymethyl cellulose changed the least.

Chemical and sensory parameters of heat-treated vacuum-packaged broiler and hen fillet products.

Chemical and Sensory Parameters of Heat-treated Vacuum-packaged Broiler and Hen Fillet Products The heat treatment of vacuum-packaged products - Sous vide processing method - that offers convenience and storage stability, combined with poultry meat marinating was used in the current study. The aim of this research was to evaluate the effect of a fruit-vegetable additive on chemical and sensory parameters of heat-treated vacuum-packaged poultry meat products made from broiler or hen fillets. The skinless fillets and other ingredients were packaged in polyamide/polyethylene (PA/PE) pouches, vacuum sealed, marinated, heat treated, and chilled rapidly. The following parameters were evaluated: moisture content (LVS ISO 1442:197), protein content (LVS ISO 937:1978), fat content (LVS ISO 1443:1973), ash content (ISO 936:996), degree of liking, and intensity of sensory properties (ISO 4121: 2003). The smallest changes in moisture content among the studied samples were observed in those prepared with the fruit-vegetable additive if compared to a raw fillet. In the process of heat treatment, the protein content in dry matter of broiler and hen fillet decreased (p<0.05), whereas fat content decreased in broiler fillet but increased in hen fillet (p<0.05). Sensory evaluation results showed that panellists preferred broiler fillet (6.6) and hen fillet (5.8) products which were prepared without the fruit-vegetable additive. Evaluation of the intensity of sensory properties showed that there do not exist significant differences in aroma, colour, flavour, and aftertaste of heat-treated vacuum-packaged hen and broiler fillet (p>0.05), but texture of broiler fillet products is more tender than texture of samples made from hen fillet.