Quality Characteristics Of Juice Research Articles

Potassium and Silicon Improve Yield and Juice Quality in Sugarcane (Saccharum officinarum L.) under Salt Stress

AbstractSoil salinity is a major abiotic stress which adversely affects the yield and juice quality in sugarcane. However, the mineral nutrient status of plant plays a crucial role in increasing plant tolerance to salinity. We investigated the effects of K and/or Si on plant growth, yield and juice quality in two sugarcane genotypes differing in salinity tolerance. Addition of K and Si significantly (P ≤ 0.05) increased K and Si concentrations and decreased the accumulation of Na+ in plants under salt stress. Cane yield and yield attributes were significantly (P ≤ 0.05) higher where K and Si were added. Juice quality characteristics like Brix (% soluble solids in juice), Pol (% sucrose in juice), commercial cane sugar (CCS) and sugar recovery in both sugarcane genotypes were also significantly (P ≤ 0.05) improved with the supplementation of K and Si. For most of the growth parameters, it was found that K either alone or in combination with Si was more effective to alleviate salt stress in both sugarcane genotypes than Si alone. Moreover, the beneficial effects of K and Si were more pronounced in salt sensitive genotype than in salt tolerant genotype. The results suggested that K and Si counteracted the deleterious effects of high salinity/sodicity in sugarcane by lowering the accumulation of Na+ and increase in K+ concentration with a resultant improvement in K+/Na+ ratio which is a good indicator to assess plant tolerance to salinity.

Alleviation of detrimental effects of NaCl by silicon nutrition in salt-sensitive and salt-tolerant genotypes of sugarcane (Saccharum officinarum L.)

Salt stress is a major environmental factor which adversely affects the crop yield and quality. However, adequate regulation of mineral nutrients may ameliorate the deleterious effects of salts and help to sustain crop productivity under salt stress. Salt-sensitive (SPF 213) and salt-tolerant (HSF 240) sugarcane genotypes were grown in gravel at 0 and 100 mM NaCl by supplying 0, 1.4 mM, 2.1 mM and 2.8 mM of Si as calcium silicate. Results revealed that plants treated with NaCl alone showed a significant (P ≤ 0.05) reduction in dry matter production, K+ concentration, cane yield and juice quality in both genotypes but the magnitude of reduction was relatively more in salt-sensitive genotype than salt-tolerant. Addition of Si significantly (P ≤ 0.05) reduced the uptake and translocation of Na+ but increased K+ concentrations particularly in shoots of both sugarcane genotypes. Cane yield and yield attributes were significantly (P ≤ 0.05) higher where Si was added. Juice quality characteristics were significantly (P ≤ 0.05) improved in salt-sensitive and salt-tolerant sugarcane genotypes with the application of Si. The results suggested that added Si interacted with Na+, reduced its uptake and transport to shoots and consequently improved cane yield and juice quality in salt-sensitive and salt-tolerant sugarcane genotypes under salt stress.

Selection of elderberry (Sambucus nigra L.) genotypes best suited for the preparation of juice

Experiments with elderberry genotypes, ripening stage and pectinolysis were carried out in order to investigate the possibility to improve different quality characteristics of elderberry juice. Raw juice was processed using either an optimised method with respect to enzyme concentration and treatment time or produced directly without any enzymatic treatment. Neochlorogenic acid, chlorogenic acid, cyanidin-3-sambubioside-5-glucoside, cyanidin-3,5-diglucoside, cyanidin-3-sambubioside, cyanidin-3-glucoside, quercetin-3-rutinoside (rutin) and quercetin-3-glucoside (isoquercitrin) were identified in the raw juice by liquid chromatography-mass spectrometry (LC-MS) and quantified by high-performance liquid chromatography-diode array detection (HPLC-DAD). The content of phenolic acids and flavonoids in elderberries were shown to be affected by berry development stage at harvest (ripening stage). Furthermore, a considerable variation in juice yield and physicochemical properties such as turbidity, soluble solids, titratable acidity, and content of phenolic acids and flavonoids was found between juices processed from elderberries by pectinolysis of different elderberry genotypes. Pectinolysis appeared not to have any major effect on juice yield and the content of phenolic acids and flavonoids in the juice compared to non-enzymatic processed juice. Factor analysis revealed correlations among quality characteristics such as soluble solids, titratable acidity, turbidity, and content of phenolic acids and flavonoids and it is shown that these correlations may be useful for the selection of elderberry genotypes best suited for the preparation of juice.

Quality degradation kinetics of pasteurised and high pressure processed fresh Navel orange juice: Nutritional parameters and shelf life

A kinetic study of post processing quality loss was conducted after high pressure processing (600 MPa, 40 °C, 4 min) or thermal pasteurisation (80 °C, 60 s) of fresh Navel orange juice. Selection of processing conditions was mainly based on pectin methylesterase inactivation. Ascorbic acid loss, colour, viscosity and sensory characteristics were measured during storage at different isothermal conditions (0–30 °C). Increased shelf life (based on ascorbic acid retention) was achieved for high pressurised compared to thermally pasteurised juice, ranging from 49% (storage at 15 °C) to 112% (storage at 0 °C). Activation energy values for ascorbic acid loss were 68.5 and 53.1 kJ/mol, respectively, for high pressurised and thermally treated juice. High pressure processing resulted in better retention of flavour of untreated juice and superior sensory characteristics compared to thermal pasteurisation. Colour change was linearly correlated to ascorbic acid loss for both types of processing. Slightly higher apparent viscosity values were determined for high pressurised juice. Industrial relevance Application of high hydrostatic pressure on orange juice industry. Fresh orange juice is a product of high commercial and nutritional value due to its rich vitamin C content and its desired sensory characteristics. High Hydrostatic Pressure (HHP) is an alternative non-thermal technology that has been proposed for application on orange juice. Such a treatment denaturates enzymes and eliminates microorganisms responsible for spoilage of orange juice without detrimental effects on the sensory and nutritional quality of juice. The effect of HHP on the stability of fresh orange juice has been studied by different research groups, while orange juices processed with the new technology have already been commercially available in Japan, U.S.A., Mexico and Europe. However, a systematic kinetic approach of the effect of HHP on different quality indexes (not only microbial spoilage) immediately after processing, as well as during a long term storage of the processed orange juice is needed, in order to achieve an optimal process design and a successful application of the new technology in orange juice industry. Such kinetic data for parameters related to the quality and nutritional value of fresh orange juice were gathered in the present work providing therefore industry with useful information for the HHP stabilization of orange juice and the production of a high quality product. Due to the great benefits of HHP compared to the conventional pasteurization that emerged from this work regarding the quality, shelf life and nutritional characteristics of fresh orange juice, HHP technology is an advantageous alternative process for high valued products like orange juice.

Effect of Deheading on Juice Quality Characteristics and Sugar Yield of Sweet Sorghum

A field experiment involving 10 sweet sorghum cultivars was undertaken to study the effect of panicle removal at anthesis on juice quality characteristics and sugar yield in sweet sorghum; control plants were left intact. The plants were harvested at grain maturity, and juice extracted from the millable stalk was analysed for sucrose contact (Pol percentage), brix and purity. Deheading treatment resulted in significant increases in millable stalk and sugar yields over those of the intact control plants. As a result of panicle removal, stem dry matter accumulation increased and side tillers were generated. The amount of juice extracted increased in the treated plants, but sucrose (Pol percentage), brix and purity levels in the juice were reduced in comparison with the intact plants.

719 PB 429 EFFECT OF GIBBERELLIC ACID ON CERTAIN PHYSICAL AND CHEMICAL PROPERTIES OF GRAPEFRUIT PEEL

Preharvest gibberellic acid (GA) applications at 10 ppm in 0.1% L-77 (v/v) surfactant or 20 ppm in 0.05% L-77 (v/v) caused `Marsh' grapefruit (Citrus paradisi Macf.) to be significantly more resistant to puncture and significantly delayed yellow color development. There was no difference between the two GA rates and applications in July were not found to be as effective as August or September applications. There was an overall significant increase in peel oil content in flavedo tissue as a result of GA treatment, but no significant difference between GA treatments. Limonin contents in GA-treated grapefruit albedo tissue were generally higher at both GA levels than in control fruit. GA treatments had no effect on juice quality characteristics and there was no difference in taste preference between GA-treated and control fruit. Because citrus fruit are resistant to attack by tephritid fruit flies prior to the occurrence of peel senescence and GA delays peel senescence, GA treatment should provide a biorational addition to existing fruit fly control strategies.