Pre-processing Cooling of Harvested Grapes Induces Changes in Berry Composition and Metabolism, and Affects Quality and Aroma Traits of the Resulting Wine

Due to the greenhouse gas increase, grapes are often exposed to high temperatures in several growing areas especially during the final developmental stages, and this is particularly true when early ripening cultivars are harvested. This may cause undesirable effects on berry metabolism and composition and wine quality, particularly concerning the aroma profile. Harvesting at night or keeping the harvested grapes in cold rooms before vinification are empirical protocols applied in specific viticultural areas. To study the effects of decreasing berry temperature after harvest, white-skinned berries (cv Vermentino) were maintained at 4 or 10°C for 24 or 48 h before processing (pre-cooling). Control grapes were kept at 22°C. Grapes cooled at 10°C for 24 and 48 h resulted richer in polyphenols and showed a significant up-regulation of genes involved in polyphenols biosynthesis (i.e., VvPAL, VvSTS2, and VvFLS1). Similar behavior was observed in samples kept at 4°C for 48 h. Pre-cooling induced specific changes in the volatile organic compound (VOC) profiles. In particular, higher amounts of a specific subcategory of terpenes, namely sesquiterpenes, were detected in cooled samples. The induction of the expression of key genes involved in terpenoids biosynthesis (VvHDR, VvDX3, VvTER, VvGT14) was detected in cooled grapes, with variable effects depending on temperature and treatment duration. In both cooled samples, the evolution of alcoholic fermentation followed a regular trend but ended earlier. Higher phenolic content was detected in wines obtained from the 10°C-treated grapes. Higher residual concentration of malic acid at the end of fermentation was detected in wine samples from grapes pre-cooled at 4°C. Sesquiterpenes also showed a general increase in wines from cooled grapes, especially after pre-cooling at 10°C for 48 h. Different sensory profiles characterized the wine samples, with the best scores in terms of general pleasantness obtained by the wine produced from grapes pre-cooled at 4°C for 24 h. These results demonstrate that pre-cooling harvested grapes induces specific effect on the VOC profile and other quality parameters of Vermentino wine, and this appears to be the result of specific metabolic and compositional changes occurring in the berries.

Physicochemical And Antioxidant Activity of Fruit Harvested From Eight Jujube (Ziziphus Jujuba Mill.) Cultivars At Different Development Stages

Jujube is a crop highly resistant to drought and salinity, making it the main fruit tree in Xinjiang. The present study was to investigate the effect of development stage on physicochemical and antioxidant activity of fruit harvested from eight jujube cultivars situated in Xinjiang, China. The content of water, ascorbic acid, total polyphenols, catechin, epicatechin, proanthocyanidin and rutin decreased during development of jujube fruit harvested from the eight cultivars, while the contents of fructose, glucose, sucrose, cAMP, and cGMP greatly increased. The antioxidant activity determined by DPPH and ABTS radical scavenging decreased through the whole growth phase. After the early stages of development, a regular trend in changes of physicochemical and antioxidant characteristic was identified, while the differences among jujube cultivars gradually reduced with complete fruit development. This work contributes to understanding the changes that take place during the development of jujube fruit, indicating that development stage influenced the change in physicochemical and antioxidant activity more than cultivar, and the initial development stage was found to be rich in AA, phenolic compounds, and antioxidant activity, whereas the red maturity stage was rich in sugars, cAMP, and cGMP.

Effect of Integrated Use of Rhizobium Inoculum and Phosphorus Fertilization on Nodulation, Growth, and Yield of Soyabean CV. Binasoybean-2

The experiment was carried out to investigate the effect of rhizobium inoculum and phosphorus fertilization on nodulation, growth, and yield of soyabean cv. Binasoybean-2 at the area of Chamberkella, East Subarnachar Upazila, Noakhali, Bangladesh, from mid-January to first week of May 2018. Four levels of Rhizobium inoculation viz: 0, 25, 50 and 75 g kg-1 and four levels of phosphorus viz: 0, 18, 36 and 54 kg P ha-1 were applied. The experiment was laid out in a randomized complete block design (RCBD) with three replications. The effect of interaction of different combinations of Rhizobium inoculation and phosphorus rates showed regular trend, although their effects on some of studied growth, and yield parameters were insignificant but most of the growth and yield parameters were significant. Among sixteen treatment combinations the highest grain yield (2.217 t ha-1) was obtained from the treatment combination of 50 g kg-1 Rhizobium inoculation and 36 kg ha-1 phosphorus which was statistically identical with 50 g kg-1 Rhizobium inoculation with 18 kg ha-1, the lowest yield (1.367 t ha-1) was recorded with control treatment. Res. Agric., Livest. Fish.8(1): 9-17, April 2021

Inoculum Size and Age Studies on Single and Mixed Strain Fermentation of Grape Juice

Single and mixed strain fermentation were compared to check the effect on properties of wine. Two strains of Saccharomyces cerevisiae (MTCC 11815 & MTCC 170) were used to study the effect of inoculum age and inoculum size on fermentation of grape juice. The inoculum sizes used were 2%, 5%, 10% and 15%, while inoculum age effect was studied using 24 h, 48 h and 60 h old inoculum. Fermentation efficiency of 77.2% was achieved in mixed strain culture using 15% inoculum, 17% initial sugars giving ethanol concentration of 6.70% (w/v) after 48 hrs. Fermentation efficiency of 84.65% was achieved with MTCC170 using 15% inoculum and 17% initial sugars giving ethanol concentration of 7.34% (w/v) in 48 hrs. Strain MTCC11815 produced 8.5% (w/v) ethanol from 17% initial sugars giving 98% efficiency using 2 and 5% inoculum. Concentration of phenolics increased with inoculum concentration while nitrogen and phosphates did not show any regular trend. The nitrogen and phosphate concentration was affected by type of strain rather than other factors.

A study on the thermal and mechanical properties of composites made of nanolignocellulose and Pebax®polymer

This study aimed at producing the biodegradable composite from lignocellulose nanofibers (LCNFs) and Pebax®thermoplastic elastomer. For this purpose, LCNFs at different levels of 0, 1, 3, and 5% were considered. The LCNFs were prepared by benzyl alcohol and then mixed with Pebax®. The liquid phase of the LCNFs and soluble polymer was prepared and then the masterbatches were mixed in an internal mixer (Model 815802, Brabender, Germany). The mixtures from the internal mixer were put into a hot press and test samples were compress-molded. The physical properties results indicated that water absorption and thickness swelling decreased by the addition of more amount of LCNF. By the addition of LCNFs to polymer, the tensile strength and modulus and impact strength were increased compared to samples without LCNF. No regular trend of enthalpy changes was observed as the content of LCNF changed. When the LCNF concentration was increased to 5%, the crystallization temperature was increased. As the LCNF concentration increased to 3%, the glass transition temperature ( Tg) was decreased, whereas by incorporating more LCNFs, the Tgwas increased. The result of the Fourier transform infrared spectra showed the peaks at 1740 cm−1which indicated the presence of polyamide bonds. Also, new peaks were observed in the range of 1400–1500 cm−1that was probably related to the presence of C−C bonds of glucose at LCNFs chains.

Achievement of Various Widebands: A Design of Wide-Slot Antennas Using Shape Blending

When designing printed wide-slot antennas, the shape or profile of the tuning stub is a key geometric structure that affects the impedance bandwidth of the antenna. This article introduces a new process for designing tuning stub shapes, which are the blended results of a diamond and a circle. By using different geometry shapes, the design could generate a series of bandwidths with a regular trend. Detailed investigations and analysis were conducted on some key geometry parameters to explore their impact on the impedance bandwidth of the antenna. To certify the new design method, several prototypes were simulated, developed, and measured. The experimental and simulated results showed good agreement with each other. The results indicate that by properly selecting various blended shapes, a BW range from 80.1 to 117.3% for a VSWR of less than 2 could be obtained, which provides a convenient model for a wideband antenna design.

Loading Rate Sensitivity of the Essential Work of Fracture, a Case Study on Pure Polypropylene

The essential work of fracture (EWF) method is gaining attention for the toughness evaluation of ductile polymers. However its establishment as a toughness criteria requires that the parameters influencing it and their extent of influence be identified. In the current study the effect of the loading rate on the EWF of pure polypropylene (PP) is investigated. Tensile tests are performed at room temperature on DENT samples with ligament lengths of 7 to 15 mm at loading rates of 2 to 32 mm/min. The results confirm the dependency of the EWF on the loading rate, though a regular trend is not observed. The nonregularity of the EWF on the loading rate is explained by the ligament dependency of the loading rate effect on the specific work of fracture. This study reveals that the similarity of the ligament lengths and loading rate are necessities to yielding comparable values of the EWF.

Study on Morphological Characteristics of Different Genotypes of Gladiolus Flower

The experiment was carried out during the period from November’2008 to October, 2009 to compare the morphology of five gladiolus flowers genotypes with respect to plant height, length and breadth of leaf, number of leaves per plant, length of flowers, breadth of flower, weight of flower, weight of single stick, length of spike, length of rachis, flowers per plant, days to reach 50% spike initiation, number of corm and cormel per plant, breadth of corm and weight of cormel per plant. The results indicated the significant variation amongst the gladiolus genotypes with respect to studied morphological characteristics as well as with yield, yield attributes and plant height. The plant height was higher (58.6cm) and lower (46.52cm) in yellow and orange /red respectively due to genotype. The lengths of leaves were almost same but higher with yellow and violet (42.25/42.05 cm) than the white and orange ones where the smallest length was recorded for red (33.36cm) one. Almost same trends were recorded for breadth of leaves with the exception of few. The average number of leaves was highest for white (12.25) followed by red, violet, orange and yellow respectively. Most of the parameters of flower characteristics did not maintain regular trend and correlation when considered in terms of sequences starting from white to red as shown in the table 1, 2 and 3. The recorded results clearly indicate that the white genotype has the best planting materials which may be planted for luxuriant growth of plants and production of excellent flowers. DOI: http://dx.doi.org/10.3329/jsf.v9i1-2.14642 J. Sci. Foundation, 9(1&2): 1-8, June-December 2011

Mechanical Properties of Kenaf - Unsaturated Polyester Composites: Effect of Fiber Treatment and Fiber Length

Kenaf fibre is a natural fibre which is growing in popularity due environmental issues and its properties as filler. Unsaturated polyester was used in this investigation via add 1% MEKP concentration ratio as the catalyst. This matrix was combined with untreated kenaf fiber with various fiber sizes (1-6) mm and (10-30) mm, alkalized with 6% NaOH solution for treated kenaf fiber to form natural fiber for two different fiber lengths composites. Composites were prepared by adding various percentages of kenaf fiber in unsaturated polyester resin. A general trend was observed whereby alkalized fiber composites possessed superior flexural strength and modulus and the maximum strength and modulus was at the 20wt% weight fraction. The length of (10-30) mm gave higher tensile and flexural properties compared to (1-6) mm. The modulus of elasticity showed a regular trend of an increase with fiber weight percent until 30% for both fiber lengths and afterwards a decrease in modulus of elasticity for composites with greater fiber weight fraction. The experimental modulus of elasticity was compared with the theoretical predictions and was found to be in good agreement with Hirsch’s model while the results obtained from Cox – Krenchel underestimating the experimental data.