The aim of this study was to evaluate dehydrated sauerkraut juice (DSJ) in bread and meat applications and investigate bioaccessibility (BAC) of TPC in the analyzed products. In current research, sauerkraut juice, dehydrated sauerkraut juice, and bread and meat products prepared with dehydrated sauerkraut juice were analyzed. For all of the samples, total phenol content, antiradical activity by ABTS+, bioaccessibility, and volatile compound profile were determined. Additionally, sensory evaluation was performed to evaluate the degree of liking bread and meat with dehydrated sauerkraut juice. The addition of DSJ increased TPC in bread and meat samples. The bioaccessibility was higher for the control samples compared to DSJ samples. It exceeded 1 and is considered as good. DSJ did not promote bioaccessibility. Benzaldehyde was the highest peak area for the Bread DSJ and Meat DSJ samples, giving a roasted peanut and almond aroma. There were no significant differences in degree of liking for structure, taste, and aroma between the control bread and the Bread DSJ, while Meat DSJ was more preferable in sensory evaluation. DSJ could be used in food applications, but further research is necessary.

White cabbage (Brassica oleracea var. capitata) is an affordable and available vegetable in local markets around the globe. It is a source of vitamins, micro and macro nutrients. The aim of this study was to compare the chemical composition of fresh and fermented cabbage juices from three different varieties. In this study vitamin C content, antiradical activity, total phenolic content, and total carotenes were determined. Results show a significant (p<0.05) influence of cabbage variety on vitamin C content. Fermentation process decreased vitamin C content in the variety 'Selma' but increased in 'Ramkila' and 'Kilpatons'. There were no significant differences between varieties (p>0.05) in the antiradical activity (by DPPH method) of fresh cabbage juice while fermentation process slightly increased it in varieties 'Ramkila' and 'Kilpatons' but significantly increased it in 'Selma' (from 96.66 for fresh to 189.54 mg 100 g-1 on dry weight (DW) for fermented). There was no consistency in the antiradical activity by ABTS⁺ method. Fermentation process slightly decreased it in variety 'Ramkila', significantly decreased it in variety 'Selma' (805.72 for fresh to 356.76 mg 100 g-1 DW for fermented) but significantly increased in 'Kilpatons' (517.09 for fresh to 845.48 mg 100 g-1 DW for fermented). Fermentation process significantly influenced contents of total phenolic compounds in two varieties-'Ramkila' (1176.1 for fresh to 1637.7 mg 100g-1 DW for fermented) and 'Kilpatons' (1106.3 for fresh to 1872.9 mg 100g-1 DW for fermented). Results showed that white cabbage or sauerkraut is not a beneficial source of carotenes.

Sauerkraut juice is rich in bioactive compounds; however, it is considered a byproduct of the production process. An innovative solution was found through the process of spray-drying to obtain sauerkraut juice powder. The aim of this study was to evaluate chemical and sensory characteristics of sauerkraut juice powder (SJP) and its application in foodstuffs. For SJP, total phenol content, antiradical activity, and nutritional value were determined, and the results showed that SJP is rich in minerals, especially calcium and potassium, as well as organic acids and vitamin C. SJP contains 12% NaCl and a total phenol content of 359.54 mg GAE 100 g⁻1 dw. SJP has umami attributes, such as sweet, sour, and salty. Sensory tests—descriptive, rate-all-that-apply, overall liking, and volatile profile determination—were carried out separately in SJP experimental samples with olive oil and sour cream. Among the sweet, sour, and salty flavours, garlic, yogurt, and mayonnaise were also mentioned. In the detection of volatile compounds, leafy and grassy green aromas with light almond were identified in the samples with olive oil and butter and rancid cheese and fishy/amine odours were identified in samples with sour cream. There were significant differences in the overall likability of samples, but the experimental samples with SJP were more popular than control samples; therefore, SJP may be used as a salt alternative in food applications.

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Experimental work was carried out in Latvia University of Life Sciences and Technologies, Faculty of Food Technology: scientific laboratory, laboratory of microbiology, biotechnology laboratory, pilot plant for fruit and vegetable processing, laboratory of equipment and processes and chemistry department. Analytical work was also carried out in collaboration with laboratory group J.S. Hamilton. Horizontal spray-drying was carried out in Tecoma Drying Technology SRL, Italy. The hypothesis of the present work – developed dehydrated and concentrated sauerkraut juice is suitable for application in foods. The hypothesis was confirmed by the following thesis. 1. Physico chemical composition of white cabbage is variety dependant and it affects the composition of sauerkraut 2. Concentration of sauerkraut juice is a suitable technology to obtain a product with high bioactive compound and mineral content. 3. Spray-drying method and carrier agent influence physico chemical composition of dehydrated sauerkraut juice. 4. Dehydrated and concentrated sauerkraut juice affects quality parameters of salad dressings, bread and meat products. The aim of the present work - to develop dehydrated and concentrated sauerkraut juice and evaluate their quality parameters. To achieve the aim, following tasks have been designated. 1. To analyse the variation in the quality parameters of cabbage and sauerkraut juice depending on variety and harvest year. 2. To evaluate quality parameters of concentrated sauerkraut juice produced by different evaporation technologies. 3. To select appropriate carrier agents for horizontal and vertical spray-drying, evaluating their influence on dehydrated sauerkraut juice quality. 4. To evaluate the effect of dehydrated and concentrated sauerkraut juice on salad dressings, bread and meat quality attributes. The work is structured into three chapters. Chapter 1. The theoretical review of the literature describes the characteristics of fresh and fermented cabbage and factors that influence their physicochemical properties. It provides information on the fermentation process. Discusses evaporation methods and encapsulation via spray drying. The review also examines the use of plant-based products in food applications, their sensory characteristics and volatile compounds. Additionally, the review explores in vitro digestion and bioaccessibility of sauerkraut juice and its products. Chapter 2. Description of materials and methods used in this study. Chapter 3. Summarises the results of research on the physicochemical properties of fresh cabbage and sauerkraut juices. It also investigates the effects of different evaporation technologies on the physicochemical properties of sauerkraut juice, and examines the use of horizontally and vertically spray-dried sauerkraut juice with various carrier agents and concentrations. The study also explores the potential applications of sauerkraut juice products in salad dressings, bread, and meat, and evaluates volatile compounds and sensory characteristics. Additionally, the study analyses the bioaccessibility after digestion in vitro. The thesis is written in English and consists of 137 pages, 31 tables and 40 figures, 194 literature sources and 2 appendixes. This study was supported by: • The European Innovation Partnership for Agricultural Productivity and Sustainability Working Group Cooperation project 18-00-A01612-000020 and • ESF project Nr. 8.2.2.0/20/I/001/TOPIC ES32—“Latvia University of Life Sciences and Technologies transition to the new doctoral funding model”. Pētījumi veikti Latvijas Biozinātņu un Tehnoloģiju universitātes, Pārtikas Tehnoloģijas fakultātē: zinātniskajā laboratorijā, augļu un dārzeņu pārstrādes pilotražotnē, procesu un iekārtu laboratorijā, mikrobioloģijas laboratorijā, biotehnoloģijas laboratorijā un Ķīmijas katedrā. Analītiskais darbs tika veikts arī sadarbībā ar laboratoriju J.S. Hamiltons. Kaltēšana ar horizontālās izsmidzināšanas kalti tika veikta Tecoma Drying Technology SRL, Itālijā. Pētnieciskā hipotēze – izstrādātās dehidrētās un koncentrētās skābētu kāpostu sulas ir piemērotas lietošanai pārtikas produktos. Promocijas darba hipotēze tika pierādīta ar četrām tēzēm. 1. Kāpostu fizikāli ķīmiskais sastāvs ir atkarīgs no šķirnes un ietekmē skābētu kāpostu sastāvu. 2. Skābētu kāpostu sulas koncentrēšana ir piemērota tehnoloģija bioaktīvo savienojumu saglabāšanai. 3. Izsmidzināšanas kaltēšanas metode un nesējviela ietekmē dehidrētas skābētu kāpostu sulas fizikāli ķīmisko sastāvu. 4. Dehidrēta un koncentrēta skābētu kāpostu sula ietekmē salātu mērču, maizes un gaļas izstrādājumu kvalitātes rādītājus. Promocijas darba mērķis - izstrādāt dehidrētu un koncentrētu skābētu kāpostu sulu un novērtēt to kvalitātes rādītājus. Darba mērķu sasniegšanai izvirzīti šādi pētnieciskie uzdevumi. 1. Analizēt svaigu un skābētu kāpostu sulas kvalitātes parametru izmaiņas atkarībā no šķirnes un ražas gada. 2. Novērtēt ar dažādām ietvaicēšanas tehnoloģijām iegūtas skābētu kāpostu sulas kvalitātes rādītājus. 3. Izvēlēties piemērotas nesējvielas horizontālajai un vertikālajai izsmidzināšanas kaltei un novērtēt to ietekmi uz dehidrētas skābētu kāpostu sulas kvalitāti. 4. Analizēt dehidrētas un koncentrētas skābētu kāpostu sulas ietekmi uz salātu mērcēm, maizes un gaļas kvalitātes īpašībām. Darbs strukturēts trīs nodaļās. 1. nodaļa. Teorētiskais literatūras pārskats apraksta svaigu un skābētu kāpostu sulas fizikāli ķīmiskās īpašības un to ietekmējošos faktorus. Tas sniedz informāciju par fermentācijas procesu. Izvērtē koncentrēšanas metodes – ietvaici, iekapsulēšanu ar izsmidzināšanas kaltēm un nesējvielām. Pārskatā izvērtēts augu blakus produktu pielietojums pārtikas produktos. Sniedz informāciju par sensoro novērtēšanu un sagremošanu kuņģa-zarnu trakta simulācijas sistēmā. 2. nodaļa. Pētījumā izmantoto materiālu un metožu apraksts. 3. nodaļa. Pētījums apkopo rezultātus par svaigu un skābētu kāpostu sulas fizikāli ķīmiskajām īpašībām. Tāpat tiek pētīta dažādu ietvaices tehnoloģiju ietekme uz skābētu kāpostu sulas fizikāli ķīmiskajām īpašībām, kā arī tiek izskatīta skābētu kāpostu sulas kaltēšana horizontālā un vertikālā izsmidzināšanas kaltē ar dažādām nesējvielām un to koncentrācijām. Pētījums arī pēta potenciālo skābētu kāpostu sulas produktu izmantošanu salātu mērcēs, maizē un gaļas produktos. Izvērtē gaistošos savienojumus un sensorās īpašības. Turklāt pētījums analizē skābētu kāpostu sulas produktu biopieejamību pēc sagremošanas in vitro. Pētnieciskais darbs ir uzrakstīts angļu valodā uz 125 lapām, ieskaitot 40 attēlus, 31 tabulu un 194 literatūras avotus un divus pielikumus. Pētījums veikts ar “Eiropas Inovāciju partnerības lauksaimniecības ražīgumam un ilgtspējīgas lauksaimniecības ražīguma un ilgtspējīgas darba grupu projekta īstenošanai” un Zinātnes un projektu attīstības centra / ESF projekti ZPAC / tēma ES32 - "LBTU pāreja uz jauno doktorantūras finansēšanas modeli" ESF projekta Nr. 8.2.2.0/20/I/001, atbalstu.