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.

Adequate, well balanced, diverse diet together with regular physical activity is considered to be the key elements for good health. The intake of macro and microelements has an important role in normal function of our bodies, ensuring enzymatic reactions, nerve impulses and other processes. However overly increased amounts of certain vitamins and minerals in the diet can be toxic. Therefore, the amount of certain nutrients needs to be consumed according to the age, gender and health condition. The aim of the research was to create new plant-based protein-enriched purees with increased protein amount, detect bioactive compound and mineral content and compare the mineral content with the recommended daily mineral intake for Latvians. For this research three recipes of new plant-based purees were created and experimentally made using organically grown ingredients from Latvia. Additional ingredients as whey-protein isolate, cod liver oil and sugar were added. Products were processed using cook-vide. All samples were tested on their mineral compound content (Na, K, Ca, P, Mg, Fe, Zn, Cu, Se), total carotene (TC) and total phenol content (TPC), antiradical activity (DPPH). The obtained data in all samples showed only trace amounts of Se per 100 g of product, on average the content of Na was only 1.2% from recommended daily intake (RDI) for Latvians per 100 g of product. The highest RDI was obtained for Fe in sample Sp1 for men 11.8%, however for women only 7.1% of RDI. Overall the highest content of bioactive compounds was found in sample Sp2.

The aim of this research was to evaluate organically grown Latvian extensive apple cultivars for production of puree for special diets with high content of bioactive compounds. Five organically grown extensive cultivars were selected for evaluation within the project: 'Antonovka', 'Filippa', 'Nicnera Zemenu', 'Rudens Svitrotais', 'Sipolins'. All these apple cultivars were evaluated fresh and after processing into puree. The content of soluble solids, titratable acids, vitamin C, total carotenes, total phenols, total flavonoids, antiradical activity (DPPH and ABTS +), and pH were determined. The cultivars with the highest soluble solids content both fresh and puree were 'Nicnera Zemenu' and 'Sipolins' with 12.7 to 13.5 Brix%, but the lowest pH value and the highest titratable acids content was detected in apple cultivar 'Antonovka'. Fresh apples of this cultivar showed also the highest vitamin C content (14.5 mg 100 g-1), but after processing into puree the vitamin C content significantly decreased and did not exceed 7.2 mg 100 g-1. Fresh apples and apple puree from cultivar 'Antonovka' had the highest content of total phenolics, total flavonoids and DPPH radical scavenging activity, whereas the lowest results showed fresh apples and puree of cultivar 'Sipolins'. Apples are not a source of caroteinoids therefore the total carotenes content in fresh apples was not higher than 0.13 mg 100 g-1 (cultivar 'Filippa') and after processing in puree it significantly (p<0.05) decreased. Apple processing had a significant (p<0.05) influence on the bioactive compounds in product.

The objective of this study was to examine the suitability of heat treatment methods on concentrations of bioactive compounds in pumpkin–guelder rose sauce. Berry hybrids 2--30--K, 2--45--K and variety ‘Krasnaya Grozdj’ were selected for further research. The juice of these fruits was used to create pumpkin–guelder rose sauce samples (experimental samples) where the pumpkin puree and guelder rose fruit juice ratio was 74.5 : 13.1. To all samples heat treatment under atmospheric conditions (traditional cooking) and vacuum cooking at 0.6 bar pressure at 85 °C and 0.2 bar pressure at 75 °C temperature was performed. These samples were compared with uncooked experimental samples. Sauce chemical evaluation showed better retention of vitamin C concentrations (per dry weight) for guelder rose variety ‘Krasnaya Grozdj’ sauces cooked at 0.2 bar pressure, compared to fresh samples. Samples that were prepared with vacuum cooking methods on average showed higher total phenol concentration, antiradical activity and total anthocyanins concentration than in control samples cooked under atmospheric conditions. These observations were consistent with reports in the literature on better preservation of bioactive compounds in plant-based products that are cooked under vacuum heat treatment at lower temperatures.

The aim of this research was to investigate the influence of processing technology and storage conditions on the quality parameters of organic pumpkin 'Uchiki Kuri' puree. Pumpkin puree was produced industrially from organically grown cultivar 'Uchiki Kuri' by heating it in a heat exchanger, and treating through sieves. Obtained puree was used to prepare four different samples: sterilized sample, frozen sample, vacuum-cooked stored at room temperature, and vacuum-cooked stored at 4±2 ℃. Samples were stored for 26 weeks. During the storage period microbiological (yeasts, moulds, Lactic acid bacteria, and Enterobacteriaceae), and chemical (total carotenes, vitamin C, total phenols, DPPH˙, ABTS˙+, water activity, and pH) parameters were analysed. Obtained results indicated that it is possible to store pumpkin purées up to six months, if those are sterilized at 110 ℃ for 15 minutes; frozen and stored at-20±2 ℃; and vacuum-cooked, packed in a bag-in-box and stored at 4±2 ℃ temperature, preserving their microbiological safety. The total carotenes content in all samples (except samples stored at 22±2 ℃ in the bag-in-box packaging) were stable during storage for 26 weeks, while vitamin C content decreased twice already after four-week storage. Significant decrease of antiradical activity DPPH˙ and ABTS˙+ after 26-week storage was observed as well.