Abstract

A field experiment was carried out during the two successive winter seasons of 2017/18 and 2018/19. The aims of the experiment were to investigate the effect of using three different mulch treatments (black polyethylene, clear polyethylene, and bare soil) on strawberry ‘Florida’ and ‘Winterstar’ cultivars (Fragaria X ananassa Duch) regarding the fruit yield, yield attributes, and some fruit quality characteristics (vitamin C, anthocyanin, acidity, TSS, and TSS: acidity), along with the financial aspects of using polyethylene mulching for strawberry productivity. Compared to the un-mulched plants, the total fruit yield of ‘Florida’ and ‘Winterstar’ plants was increased by ~40-49% and 17-18%, respectively in the black plastic mulching in the two years. Clear plastic mulching was accompanied by an increased total yield of ‘Florida’ by 19-34%, while decreased ‘Winterstar’ fruit yield by 14-24%. Regarding vitamin C content, the main effects of mulching treatment showed that plants grown in black plastic mulching had significantly higher vitamin C content than clear plastic (both seasons) or no mulching (second season). ‘Florida’ plants in the black plastic mulching achieved significantly the highest vitamin C levels compared to the other treatments. Similarly, ‘Florida’ plants in the black plastic mulching had higher TSS content than the other mulching treatments. Depending on the cultivar used and the growing season, plastic mulching (whether clear or black) was beneficial in improving the fruits anthocyanin content compared to the un-mulched plants. In conclusion, plastic mulching (especially the black) was helpful in improving fruits contents of vitamin C and anthocyanin compared to the un-mulched plants. Regarding the financial aspect, using black plastic mulching for strawberry production in Assiut governorate was more profitable than the un-mulched farm.

Keywords: Black Plastic Mulching, Clear Plastic Mulching, Vitamin C, Anthocyanin, TSS, Financial Aspect.

Abstract

This work was carried out at the experimental orchard of Pomology Department, Faculty of Agriculture, Assiut University to study the effect of spraying gibberellic acid (GA3) (25 and 50 ppm), camphor oil (2 and 3 cm3 /L) and a mixture of them on fruit quality of "Manfalouty pomegranate" cultivar. The selected pomegranate trees were divided into three groups, the first group was sprayed at 6 weeks after fruit setting (the 1st time), the second group was sprayed at 6 weeks after the 1st time (The 2nd time), and the third group was sprayed twice (at the 1st and the 2nd time) during 2016 and 2017 seasons. Since both of GA3 and camphor oil play an important role in physiological and biological processes of plants. Recently, camphor oil was successfully used in synthezing carbon nanotubes as chemical vapor deposition process (Kumar and Ando, 2007). Hence, the main objective of this study was to examine spraying a mixture of GA3 (25 and 50 ppm) plus camphor oil (2 and 3 cm3 /L) on improving fruit quality of Manfalouty pomegranate cv. According to the obtained results of this investigation all the treatments, specially the mixture of GA3 and camphor oil increased fruit weight (g), aril weight/fruit, juice volume (cm3 )/100 g arils as well as the TSS % and TSS/TA ratio in fruit juice. Also, this mixture slightly decreased both of peel weight/fruit and the titratable acidity % (TA) during the two studied seasons. Therefore, it could be recommended that spraying with a mixture of gibberellic acid (GA3) plus camphor oil for improving fruit quality of Manfalouty pomegranate cv. under the conditions of this study.

Keywords: Gibberellic acid, Camphor oil, Manfalouty Pomegranate cv., Fruit quality

Oxidized gellan gum (OGG) hydrogel beads as delivery systems for resveratrol were fabricated by ionic cross-linking with calcium chloride (CaCl₂). The degree of oxidation (DO) and CaCl₂ concentration had significant influences on the formation and functional properties of hydrogel beads. The resveratrol encapsulation efficiency (66.43%–79.84%) and loading capacity (4.15%–5.05%) of OGG hydrogel beads were enhanced as DO increased. The hydrogel beads exhibited a uniform spherical shape as observed by scanning electron microscope. Fourier transform infrared spectroscopy analysis confirmed that hydrogen bonds and ionic interaction participated in the formation of hydrogel beads. X-ray diffraction analysis revealed that the physical state of resveratrol was changed from crystalline to amorphous form after encapsulation. Furthermore, the physical stability and antioxidant capacity evaluation demonstrated that the hydrogel bead fabricated with DO80 OGG and CaCl₂ concentration of 1.0 M could provide high protection for resveratrol against degradation by environmental stresses and maintain its antioxidant capacity. The DO and CaCl₂ concentrations could modulate the in-vitro release behaviors of hydrogel beads and obtain a good small intestinal-targeted release of resveratrol at high DO and medium CaCl₂ concentration. These findings suggested that a promising delivery system for encapsulating bioactive ingredients can be fabricated by rational design.

Animal fats and shortenings are frequently used in the preparation of different food formulations. However, these fat ingredients are rich in saturated fatty acids, and partially hydrogenated shortening contains trans fats, which have been associated to an increased risk of coronary heart disease. Consequently, nutritionists recommend a reduction in the content of saturated and trans fatty acids in the human diet. At the same time, eliminating solid fats from the food industry is a difficult endeavor because they are necessary for many food products to have the desired quality attributes. As a result, food scientists and technologists are working together to develop healthy fat substitutes for saturated and trans fats. Structuring edible oils into solid-like oleogels has attracted increasing interest from scientists, and many types of oleogels have been developed. Although some oleogels have shown potential applicability, the application of oleogels in the food industry at a commercial scale is limited because of some technological challenges. Therefore, this article aimed to explore recent advances in research performed to study the suitability of oleogels for the application in different food products. Challenges facing the application of oleogels in the food industry and future perspectives are also discussed.

Outer shells and inner blocklets were isolated from normal and waxy wheat A- and B- starch granules. Microstructural, molecular, and architectural characteristics of the isolated shells and blocklets were investigated using different methods and techniques. The results revealed that the outer shells were flake and net pocket shaped, with a compact surface and mass fractal. On the other hand, inner blocklets exhibited spherical, beaded, and rod shapes with a typical V-type crystalline structure. Crystallinity, degree of short-range order, amylopectin and amylose molecular weight, amount of intramolecular hydrogen bonds, and the average of shorter semicrystalline lamellae repetition distance varied between outer shells and inner blocklets, as well as depending on the type of wheat starch granules, i.e. normal and waxy wheat A- and B- starch granules. The branch chain length distribution of amylopectin affected the thickness of amorphous and crystalline regions, and the crystal order degree influenced the fractal and morphological characteristics of outer shells and inner blocklets. Additionally, amylose and amylopectin of inner blocklets were polymerized to form larger amylose and amylopectin molecules and develop the outer shells. The obtained findings give a theoretical basis for understanding the relationship between molecular structure and architectural characteristics of starch.

In this study, proso millet starch was isolated and subjected to treatment with ultra-high pressure (UHP), cold plasma (CP), or their combination to modify its functional properties. The changes in structural, physicochemical, and digestive properties of proso millet starch after these treatments were investigated. The proso millet native starch granules showed irregular and polygonal shapes with a smooth surface. Treatments with CP or UHP at low pressures did not change the morphological properties or crystalline structure type of proso millet starch granules, while the treatment with UHP at 600 MPa and CP resulted in a complete gelatinization of starch. Also, UHP treatment at high pressure, followed by CP treatment, destroyed the partial crystalline region and reduced the short-range order of proso millet starch. Besides, a combination of UHP and CP treatment promoted the depolymerization of long chains in proso millet starch. Moreover, the combined treatments could enhance the resistance to high temperature and shearing and improve the pasting stability of starch. Furthermore, the combined treatment could increase the slowly digestible starch content. Therefore, the combination of UHP and CP treatment can be suggested for modifying the functional properties of proso millet starch and promoting its industrial applications.

Studies in recent years have shown that aquatic pollution by microplastics (MPs) can be considered to pose additional stress to amphibian populations. However, our knowledge of how MPs affect amphibians is very rudimentary, and even more limited is our understanding of their effects in combination with other emerging pollutants. Thus, we aimed to evaluate the possible toxicity of polyethylene MPs (PE-MPs) (alone or in combination with a mix of pollutants) on the health of Physalaemus cuvieri tadpoles. After 30 days of exposure, multiple biomarkers were measured, including morphological, biometric, and developmental indices, behavioral parameters, mutagenicity, cytotoxicity, antioxidant and cholinesterase responses, as well as the uptake and accumulation of PE-MPs in animals. Based on the results, there was no significant change in any of the parameters measured in tadpoles exposed to treatments, but induced stress was observed in tadpoles exposed to PE-MPs combined with the mixture of pollutants, reflecting significant changes in physiological and biochemical responses. Through principal component analysis (PCA) and integrated biomarker response (IBR) assessment, effects induced by pollutants in each test group were distinguished, confirming that the exposure of P. cuvieri tadpoles to the PE-MPs in combination with a mix of emerging pollutants induces an enhanced stress response, although the uptake and accumulation of PE-MPs in these animals was reduced. Thus, our study provides new insight into the danger to amphibians of MPs coexisting with other pollutants in aquatic environments.