Vitalijs Radenkovs

Influence of 1-Methylcyclopropene and ULO Conditions on Sensory Characteristics of Apple Fruit Grown in Latvia

Abstract The aim of the study was to evaluate the influence of 1-methylcyclopropene (1-MCP) treatment and ultra-low oxygen (ULO) storage conditions on the sensory characteristics of apples. Two apple storage technologies were tested in this study: cold storage under traditional conditions in combination with 1-MCP treatment, and ULO storage with two different compositions of a gas mixture. Apples were stored for 6 months. After storage, the sensory characteristics were analysed. Sensory evaluation showed that storage technology affected the sensory characteristics and panelists’ acceptability. Distinctive differences were found between apples stored under controlled atmosphere and traditional conditions. Trained panelists highlighted that samples stored under controlled atmosphere had pronounced juiciness and color, while 1-MCP-treated apples stored in cold were sweeter and more aromatic. Apples of the autumn cultivar ‘Auksis’, was perceived considerably higher after harvest and before long-term storage, compared with other cultivars. During 6 months of storage in controlled atmosphere, the sensory quality of these apples remained intact. Also, the sensory quality of fruit of the winter cultivar ‘Sinap Orlovskij’ throughout 6 months of its storage in controlled atmosphere remained intact. Besides, it was noticed that apples stored in controlled atmosphere were juicier and more aromatic with intense color. There is a positive effect of 1-MCP treatment on maintenance of apple quality stored in normal atmosphere for 6 months. With regard to some quality parameters and sensory attributes, 1-MCP-treated apples stored under normal atmosphere are comparable to those stored under ULO conditions.

Profile of lipophilic antioxidants in the by-products recovered from six cultivars of sour cherry (Prunus cerasus L.)

Abstract The content of tocochromanols and carotenoids in kernels recovered from fruit pits of six sour cherry (Prunus cerasus L.) cultivars was studied. The highest concentration was noted for γ-T (23.50–52.76 mg/100 g dry weight basis (dw)). Considerably, lower amounts compared to γ-T were detected for α-T, δ-T and α-T3 (5.74–13.33, 2.74–4.54 and 0.30–1.16 mg/100 g dw, respectively). The β-T and γ-T3 were quantified only in minor levels. The total amount of tocochromanols was in the range 41.69–63.48 mg/100 g dw. The levels of total carotenoids ranged between 0.17 and 0.39 mg/100 dw. The concentration of tocochromanols and carotenoids in kernels of different sour cherries is cultivar-dependent. A significant correlation (r = 0.985, p < 0.001) has been observed between the total content of tocochromanols in kernels and scavenging of free radicals DPPH by native lipophilic antioxidants in the by-products of sour cherry.

Varied Composition of Tocochromanols in Different Types of Bran: Rye, Wheat, Oat, Spelt, Buckwheat, Corn, and Rice

The profiles of tocopherol (T) and tocotrienol (T3) homologues in 37 samples of seven different types of bran (rye, wheat, oat, spelt, buckwheat, rice, and corn), available on the Polish market, were studied. Tocochromanols were identified and quantified by reverse phase-high-performance liquid chromatograph/fluorescence detector and reverse phase-ultra performance liquid chromatography-electrospray ionization/mass spectrometry. Only rice bran contained all eight tocochromanol types. Corn bran lacked β-T3; rye, wheat, oat, and spelt bran lacked γ-T3 and δ-T3; and buckwheat bran lacked β-T3, γ-T3, and δ-T3. In buckwheat and corn bran tocopherols predominated (98 and 78%, respectively); whereas rye, wheat, oat, spelt, and rice bran were rich in tocotrienols (78, 76, 66, 87, and 66%, respectively). The average total tocochromanol contents in the oat, corn, spelt, buckwheat, wheat, rye, and rice bran were 5.5, 16.2, 15.8, 14.7, 12.8, 10.7, and 9.1 mg/100 g of dry weight, respectively. Tocochromanol concentrations in samples of the same type bran from different sources varied considerably. Better labeling of bran products to reflect this variation would assist with control of vitamin E daily dietary requirements.

Assessment of Shelf-Life Ability of Apples cv. ‘Auksis’ after Long-term Storage Under Different Conditions

Abstract The objective of the current research was to ascertain the shelf-life ability of apple ‘Auksis’ after 6 months of cold storage under different conditions. The effect of storage conditions such as: cold storage under normal atmosphere (NA), 1-methylcyclopropene (1-MCP) + cold storage, and ultra-low oxygen (ULO)-controlled atmosphere (CA) [2.0% CO2 and 1.0% O2 (ULO1) and 2.5% CO2 and 1.5% O2 (ULO2)] on the quality of apples during shelf-life was evaluated. Apple fruits immediately after cold storage and after 25 days of maintaining at market condition had been evaluated. The physical (firmness, weight losses), chemical (total soluble solids and acid contents), and sensory (aroma, taste, acidity, sweetness, juiciness, and color) characteristics of apples had been evaluated after 5, 10, 15, 20, and 25 days to ascertain maximal shelf-life. Results from sensory evaluation indicated that apples treated with 1-MCP and stored at NA were characterized with distinctive aroma, whereas apples stored under CA were poor in sweetness and had remarkable acidity and juiciness. Apples that were stored in cold had pronounced aroma and color but without taste. Based on the evaluation by panelist, maximum shelf-life of apples that were kept under cold storage and ULO1 was 15 days, whereas that of apples that had been treated with 1-MCP and stored at NA and those stored in ULO2 was 25 days.

Valorization of Wild Apple (Malus spp.) By-Products as a Source of Essential Fatty Acids, Tocopherols and Phytosterols with Antimicrobial Activity

The amplified production of fruit as well as burgeoning demand for plant-made food products have resulted in a sharp increase of waste. Currently, millions of tons of by-products are either being discarded or utilized rather ineffectively. However, these by-products may be processed and further incorporated as functional ingredients in making high-value food products with many physiological and biochemical effects. The chemical analysis of pomace oils using gas chromatography-mass spectrometry (GC/MS) and reversed-phase-liquid chromatography coupled with fluorescence detector (RP-HPLC/FLD) systems led to the identification and quantification of 56 individual lipophilic compounds including unsaturated, polyunsaturated and saturated fatty acids, as well as phytosterols and four homologs of tocopherol. The oils recovered from by-products of Malus spp. (particularly cv. “Ola”) are rich in fatty acids such as linolenic (57.8%), α-linolenic (54.3%), and oleic (25.5%). The concentration of total tocopherols varied among the Malus species and dessert apples investigated, representing the range of 16.8–30.9 mg mL−1. The highest content of total tocopherols was found in M. Bernu prieks, followed by M. cv. “Ola”, and M. × Soulardii pomace oils. A significantly higher amount of δ-tocopherol was established in the oil of M. Bernu prieks, indicating that this species could be utilized as a natural and cheap source of bioactive molecules. β-Sitosterol was the prevalent compound determined in all tested pomace oils with a percentage distribution of 10.3–94.5%. The main triterpene identified in the oils was lupeol, which varied in the range of 0.1–66.3%. A targeted utilization of apple pomace would facilitate management of tons of by-products and benefit the environment and industry.

Comparison of three storage techniques for post-harvest quality preservation of six commercially available cultivars of apple

ABSTRACT To evaluate the influence of 1-methylcyclopropene (1-MCP) treatment and ultra-low oxygen storage systems (ULO 1 2.0 kPa CO2 and 1.0 kPa O2) and (ULO 2 2.5 kPa CO2 and 1.5 kPa O2) on the chemical composition, sensory quality and proliferation intensity of microorganisms during long-term storage of apple, a two-year study was conducted, using two autumn cultivars: ‘Auksis’, ‘Orlik’, and four winter cultivars: ‘Antej’, ‘Belorusskoje Malinovoje’, ‘Sinap Orlovskij’ and ‘Zarja Alatau’, grown in cool climate. Fruits were stored for 6 months and the alterations in weight, soluble solid content, titratable acidity, firmness and microorganism development on fruit surface were examined. To better understand consumers’ attitude towards apple quality, the sensory analysis was performed. The results indicated that the most substantial positive effect on physical and chemical parameters and sensory quality has been achieved when ultra-low oxygen storage was applied. In general, all cultivars had retained better quality with regards to acids and soluble solids content. Likewise storage under ultra-low oxygen conditions, 1-Methylcyclopropene has positioned a strong positive effect on apple flesh firmness. Apples stored under different circumstances showed different contamination frequency and diversity of microorganisms, where the lowest incidence of microbial activity was found on apples stored under ultra-low oxygen, whereas the highest incidence of microbial activity was found on apples kept under storage in air.