Effect of Storage Temperatures on Physico-Chemicals, Phytochemicals and Antioxidant Properties of Watermelon Juice (Citrullus lanatus)

Watermelon (Citrullus lanatus) consists of high moisture content and is favoured for its juice products. The popular fruit has a tempting taste, sweet aroma and attractive flesh colour. It is enriched with phytochemicals and antioxidant properties that are beneficial to human health. Due to convenience, the majority of individuals are likely to consume watermelon juice. However, little is known about the fruit juice storage and temperatures that may affect its beneficial properties. This study investigated the effect of storage temperature at room temperature, refrigerator cold, refrigerator freeze and freeze-dried, and analyzed the juice physico-chemicals (weight loss, pH, ash, moisture, total soluble solid, browning and turbidity), phytochemicals (total phenolic, total flavonoid, lycopene and β-carotene) and antioxidant scavenging activities during 9 days of storage. The results showed that watermelon juice was affected by storage temperatures and conditions with significant changes in physico-chemical appearance and decrease in total phytochemical content, thus consequently affecting their antioxidant activities during 9 days of storage. Although fresh watermelon juice can be consumed for its high nutritional values, freeze-drying is the preferable technique to retain its benefits and to delay juice degradation.

FRUIT QUALITY OF NEW INTRODUCED PLUM CULTIVARS UNDER THE CONDITIONS OF BULGARIA

Prunus domestica L. is one of the most commonly grown fruit species in Bulgaria due to its high ecological adaptation and multiple ways of fruit marketing. Fruit quality is associated with attributes such as appearance, texture, taste and colour. Breeding and new cvs. introduction are in constant search for cultivars with better fruit quality that would answer the increasing consumer requirements. In 2013 the Romanian plum cvs. ‘Pitestean’, ‘Roman’, ‘Romanta’, ‘Carpatin’ and ‘Tita’ were introduced in Bulgaria and planted in a collection orchard at the Fruit Growing Institute, Plovdiv. The study was conducted in the period 2016-2021. It aimed to evaluate the fruit quality when the cultivars are grown under the agro-environmental conditions of the region. For obtaining this objective, fruit weight, fruit flesh firmness, TSS (°Brix), skin colour with and without wax bloom and fruit flesh colour were measured. For evaluating consumer acceptance, a sensory analysis was performed. ‘Roman’ had the largest fruits with an average fruit weight of 46.66 g and the highest TSS content – 18.2°Brix. There were significant differences in the colour parameters L*, a*, b*, Chroma and Hue between the cultivars and the wax bloom had a significant effect on colour parameters. All fruits were appreciated by the testing panel of consumers and their taste qualities were evaluated as good and very good.

Comparative Study of Potato (Solanum tuberosum L.) and Sweet Potato (Ipomoea batatas L.): Evaluation of Proximate Composition, Polyphenol Content, Mineral and Antioxidant Activities

The objective of the present study was to differentiate and compare the proximate composition, minerals, flesh colour, phenolic composition, and antioxidant activities of varieties of white-fleshed sweet potato (WFSP) and potato (WFP) locally grown in Pakistan. The results showed that WFP presented higher moisture and crude fat content, while WFSP offered better ash, crude protein, and crude fibre contents. Colour analysis revealed that WFSP and WFP showed the highest L* (lightness) values and exhibited the maximum total phenolic content and total flavonoids content of 9.27 ± 0.88 mg GAE/g and 19.01 ± 0.66 mg QE/g. In vitro, results demonstrated that WFSP possessed better antioxidant activity with the highest ferric reducing antioxidant power of 58.67 ± 0.22 mM Fe2+/g and DPPH scavenging activity of 39.12 ± 0.33% compared to WFP. It is concluded that WFSP possesses a better proximate and mineral profile followed by higher antioxidant activity.

Identification of the genetic diversity of sweet potato germplasm based on quantitative morphological characters

Sweet potato is one of the prospective food crops to be used as an export commodity. Information on genetic diversity of sweet potato is needed as a consideration for the improvement of superior sweet potato varieties that have export quality. The research was conducted in Wringin Songo village, Tumpang, Malang Regency. The materials used were 150 sweetpotato accessions in total that consisting of: 19 superior varieties, 38 local clones, 1 introduced variety and 92 promising clones. This experiment was arranged in randomized block design (RBD) with two replications. The qquantitative morphological variables such as: potential yield, tuber weight, dry matter, stover weight, harvest index and number of tubers plot−1 were observed. The results showed that the genetic diversity was quite high in the sweet potato germplasm, there were 41 clones that had yield potential (≥ 30 t ha−1). Some of these clones were prospective to be used as parents for crossing due to their ability to flower. Two sweet potato clones (MSU 10001-18 and MSU 07030-64) with dark purple flesh colour, Kidal variety with yelow flesh color and above 30% tuber dry matter have the criteria required for export market.

Genetic Parameters and Genome-Wide Association Studies of Quality Traits Characterised Using Imaging Technologies in Rainbow Trout, Oncorhynchus mykiss

One of the top priorities of the aquaculture industry is the genetic improvement of economically important traits in fish, such as those related to processing and quality. However, the accuracy of genetic evaluations has been hindered by a lack of data on such traits from a sufficiently large population of animals. The objectives of this study were thus threefold: (i) to estimate genetic parameters of growth-, yield-, and quality-related traits in rainbow trout (Oncorhynchus mykiss) using three different phenotyping technologies [invasive and non-invasive: microwave-based, digital image analysis, and magnetic resonance imaging (MRI)], (ii) to detect quantitative trait loci (QTLs) associated with these traits, and (iii) to identify candidate genes present within these QTL regions. Our study collected data from 1,379 fish on growth, yield-related traits (body weight, condition coefficient, head yield, carcass yield, headless gutted carcass yield), and quality-related traits (total fat, percentage of fat in subcutaneous adipose tissue, percentage of fat in flesh, flesh colour); genotypic data were then obtained for all fish using the 57K SNP Axiom® Trout Genotyping array. Heritability estimates for most of the 14 traits examined were moderate to strong, varying from 0.12 to 0.67. Most traits were clearly polygenic, but our genome-wide association studies (GWASs) identified two genomic regions on chromosome 8 that explained up to 10% of the genetic variance (cumulative effects of two QTLs) for several traits (weight, condition coefficient, subcutaneous and total fat content, carcass and headless gutted carcass yields). For flesh colour traits, six QTLs explained 1–4% of the genetic variance. Within these regions, we identified several genes (htr1, gnpat, ephx1, bcmo1, and cyp2x) that have been implicated in adipogenesis or carotenoid metabolism, and thus represent good candidates for further functional validation. Finally, of the three techniques used for phenotyping, MRI demonstrated particular promise for measurements of fat content and distribution, while the digital image analysis-based approach was very useful in quantifying colour-related traits. This work provides new insights that may aid the development of commercial breeding programmes in rainbow trout, specifically with regard to the genetic improvement of yield and flesh-quality traits as well as the use of invasive and/or non-invasive technologies to predict such traits.

The Effect of Mechanical Vibration during Transport under Model Conditions on the Shelf-Life, Quality and Physico-Chemical Parameters of Four Apple Cultivars

The study assessed the changes in the quality and physical and chemical parameters of apples of four cultivars (‘Gala’, ‘Idared’, ‘Topaz’, ‘Red Prince’) subjected to mechanical vibration during transport under model conditions and after storage (shelf-life). Quality changes in apples were evaluated based on skin and flesh colour, total soluble solids, dry matter, firmness, titratable acidity, pH value, total polyphenol content, and antioxidant capacity. The vibration applied at a frequency of 28 Hz caused changes in the above parameters, which were visible also after storage and depended on the cultivar, but often did not show any clear trend or direction or were not statistically significant. The values of the total colour difference factor ΔE showed considerable variations in the skin colour but only small variations in the flesh colour of individual cultivars. Vibration resulted in a decrease in firmness. Variations in dry matter, total soluble solids, pH, and titratable acidity were small, often insignificant. Mechanical vibration and storage led to an increase in the polyphenol content and antioxidant capacity of all studied cultivars. The greatest stability of quality parameters, relatively high content of bioactive compounds, and antioxidant capacity were observed for ‘Red Prince’. The lowest quality parameters were noted for ‘Gala’. The analysed cultivars continued to show a high level of antioxidant capacity after treatment, which allows the conclusion that they remain a good source of bioactive compounds after transport and short-term storage.

Yield parameters, antioxidant activity, polyphenol and total soluble solids content of beetroot cultivars with different flesh colours

This study aimed to evaluate yield parameters, antioxidant activity (AOA), total polyphenol content (TPC) and total soluble solids (TSS) in beetroot cultivars with different flesh colours. Field experiments were established at the Slovak University of Agriculture in Nitra in 2016 and 2017. Within the study, 16 beetroot cultivars were tested, including 11 red-fleshed (‘Boltardy’, ‘Boro’ F1, ‘Crosby Egyptian’, ‘Cylindra’, ‘Detroit Globe’, ‘Detroit 2’, ‘Egyptian Turnip Rooted’, ‘Opolski’, ‘Pablo’ F1, ‘Renova’ and ‘Taunus’ F1), 2 yellow-fleshed (‘Boldor’ F1 and ‘Golden’), 2 white-flesh cultivars (‘Albino’ and ‘White Detroit’) and 1 red-white fleshed cultivar (‘Chioggia’). All beetroot cultivars with red flesh colour showed higher AOA and TPC than different-coloured beetroot cultivars. The highest root yield was found in the white-fleshed beetroot cultivar ‘Albino’ (37.80–41.91 t · ha−1). The highest root weight was found in the white-fleshed beetroot cultivar ‘White Detroit’ (362.4–412.1 g). The highest AOA (819.19–972.50 mg TEAC · kg−1 d.w.) and TPC (2,387.70–2,731.00 mg · kg−1 d.w.) were found in the red-fleshed beetroot cultivar ‘Pablo’ F1. Different-coloured cultivars of beetroot were characterised by a lower content of TSS (6.4–8.8 ºBRIX) than cultivars with typical, red flesh colour (7.8–10.8 ºBRIX). Results clearly indicate that cultivar, or flesh colour, is showed as a significant factor influencing the quality of beetroot. Knowing of yield potential and quality of beetroot cultivars is important for growers as well as consumers. Results of this study indicate that white-fleshed cultivars of beetroot are characterised by high yield potential but lower quality, including lower AOA, TPC and TSS.