Kristine Ramane, Envija Strautniece and Ruta Galoburda
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.
In recent years, due to the health problems and better life expectancy, natural sources of bioactive substances have gained wide interest. Sea buckthorn is well known as a valuable plant and is widely used in traditional medicine for the treatment of diseases and disorders. A considerable amount of literature has been published on sea buckthorn berries, although all parts of sea buckthorn plant are considered as a source of a large amount of biological active substances, and believed to have beneficial health effects. Therefore, vegetative parts would be a good raw material not only for medicinal, cosmetic and pharmaceutical properties, but also for the food industry. This has increased the research on different sea buckthorn vegetative parts and their extract activity and toxicity. Sea buckthorn leaves have attracted interest during the past few years as the most promising source of active compounds after berries. They contain a wide range of hydrophilic and lipophilic bioactive compounds, which exhibit remarkable anti-oxidant potential together with anti-bacterial, anti-viral, anti-tumour and anti-inflammatory activity. Therefore, extracts of the plant leaves could be used as natural replacements for synthetic additives and for food products with functional properties. This creates the need to investigate the biochemical content of sea buckthorn vegetative parts grown in Latvia.
Igor Sepelevs, Valentina Stepanova and Ruta Galoburda
The main objective of the present study was to investigate the effect of spray- and freeze-drying techniques on the microencapsulation of a gallic acid compound using the acid-hydrolyzed low dextrose equivalent potato starch as a wall material. During the experiment, it was possible to achieve encapsulation efficiency of 70–84% for the freeze-dried and 65–79% for spray-dried samples, without statistically significant difference (P>0.05) in the encapsulation efficiency between the mentioned methods. Spray-dried samples formed spherical capsules with a higher number of micropores. Meanwhile, freeze-dried samples were shapeless, exposed larger pore volume (from 2.4×10−3 to 9.5×10−3 cm3/g against 1.2×10–3 4.9×10−3 cm3/g; analyzed by Barrett-Joyner-Halenda method) and overall higher surface area (0.632–1.225 m2/g against 0.472–1.296 m2/g; analyzed by Barrett-Joyner-Halenda method). Due to this fact, more gallic acid molecules were exposed to environmental factors and can be counted as losses. In addition, freeze-dried samples demonstrated lower water activity than spray-dried samples (0.075±0.014 against 0.178±0.008). Results showed that it is not practical to use freeze-drying for modelling encapsulation for food industry without a special necessity for protection of easily degradable chemical compounds. The present work makes a basis for the future studies of the microencapsulated phenolics application in food production.
Asnate Ķirse, Daina Kārkliņa, Sandra Muižniece-Brasava and Ruta Galoburda
The study was carried out to investigate the influence of sous vide treatment (80 °C/15 min) and high pressure processing (700 MPa/10 min/20 °C) on nutritional characteristics of cowpea (Vigna unguiculata (L.) Walp. cv. Fradel) and maple pea (Pisum sativum var. arvense L. cv. Bruno) spreads after processing and 62-day storage at 5 ± 1 °C temperature, to evaluate overall acceptance of processed pulse spreads after 22-day storage and to analyse nutrient coverage of pulse spreads compared to reference intake for adolescents and adults. Pulse spreads were made of cooked pulse seeds to which salt, citric acid, oil, and seasoning was added. Pulse spreads were hermetically sealed under vacuum in PA/PE and PET/ALU/PA/PP pouches. Nutritional composition was determined according to standard methods; overall acceptance was determined using a 5-point hedonic scale. Nutrient coverage by one serving of pulse spreads for adolescents and adults was compared to nutrient recommendations given by the Ministry of Health of the Republic of Latvia. The results suggest that processing technologies and packaging materials did not influence nutritional value of pulse spreads (p > 0.1). Hedonic evaluation by consumers (n = 90) showed that processing technologies did not influence the overall acceptance of cowpea and maple pea spreads (p > 0.1).
Lolita Tomsone, Zanda Kruma, Ruta Galoburda and Thierry Talou
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.
Elga Šne, Dalija Segliņa, Ruta Galoburda and Inta Krasnova
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.
Solvita Kampuse, Liene Ozola, Evita Straumite and Ruta Galoburda
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.
Laila Vilmane, Sanita Zute, Evita Straumīte and Ruta Galoburda
The rising attention globally on the use of oats and the beneficial effect of oat compounds in nutrition has also increased interest in oat production in Latvia. The aim of this study was to evaluate protein, amino acid and gluten content in husked and hulless oat grains grown in organic and conventional farming systems. Two hulless oat (Avena sativa L.) genotypes - the breeding line '33793' and the variety 'Stendes Emilija' and one husked oat variety 'Lizete' from the State Stende Cereal Breeding Institute - were cultivated in 2013 under conventional farming methods using three nitrogen (N) application rates (80, 120, and 160 kg·ha-1) and under organic farming. Protein content was determined by Kjeldahl method, amino acid composition by high-performance liquid chromatography method using Waters AccQ Tag, and gluten content by Sandwich R5 ELISA. The results showed that oat genotype had significant effect p < 0.001) on protein and gluten content, as well as on amino acid composition. The applied amount of fertiliser did not have significant effect on the studied quality parameters, but the growing system did (p < 0.001). Higher content of protein was observed in hulless oat samples, compared to that in husked oat samples. There was also a significant difference (p = 0.01) in the total amount of amino acids between husked and hulless oat samples. In hulless oat variety 'Stendes Emilija' and hulless breeding line '33793' the content of gluten was similar and two times higher than in the husked oat variety 'Lizete'. Further breeding work is necessary to obtain oats with a lower content of gluten-like proteins.
Marika Liepa, Jelena Zagorska, Ruta Galoburda and Svetlana Kostascuka
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.
Sigita Boča, Ruta Galoburda, Imants Skrupskis and Dace Skrupska
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.