Juice Yield Research Articles

Characterization in Clonal Selections of Citrus X latifolia Tanaka ex Q. Jiménez

Objective: To physically and chemically characterize clonal selections of Persian lime(Citrus x latifolia Tanaka ex Q. Jiménez).Design/Methodology/Approach: The principal components analysis was employed,using a mixed data factorial analysis model. Genotype distribution was graphed usingprincipal components with the k-medoids method, while a Gower’s dissimilarity matrixwas determined for the conglomerate analysis and a dendrogram was developed usingWard’s minimum variance cluster method. For the morphological characterization of thefruits, the study considered the following trees: Citrus volkameriana, Citrus macrophylla,Citrus paradisi X Poncirus trifoliata, X Citroncirus spp., and Citrus X aurantium. Thefruit’s diameter, length, weight, color, and shape were analyzed, in addition to its baseshape, tip shape, surface texture, albedo adherence, number of seeds, ripening rate,juice weight, juice yield, pH, °Brix, and titratable acidity. Data were analyzed using Rsoftware and the factoextra and FactoMineR packages.Results: The physical and chemical traits of Persian lime fruit vary due to thecorrelations between the types of rootstock that are cultivated in the citrus zone studied. Study Limitations/Implications: Farmers do not know which clone or type of plantmaterial they propagate; they simply select clones that show outstanding morpho-agronomical traits.Findings/Conclusions: The morphological diversity and quality of the fruit is related tothe type of rootstock used in its propagation, in addition to internal and external traits inCitrus macrophylla standing out in fruit quality.

Scab Resistant Apple Cultivars for Juice Production

Abstract The purpose of this experiment was a selection of scab resistant apple cultivars suitable for juice production. Special attention was paid to cloudy juices. During three successive seasons, apple cultivars were processed into juices using laboratory method of juice extraction. Considering the possibility of both clear and cloudy juice production, apples were pressed with and without mash enzymation. The parameters investigated were: pressing yield, titratable acidity, soluble solids, juice density, and juices’ sensory characteristics. Average values indicate that all the cultivars fulfilled the requirements of the Code of Practice of the European Fruit Juice Association concerning investigated chemical components, however, in single years, there were some deviations that should be taken into consideration offering single cultivar juices. Considering a low yield of juice without mash enzymation (below 70%), cultivars ‘Renora’ and ‘Retina’ are not recommended for cloudy juice production. Sensory quality of juices, irrespectively if cloudy or clear, depended mostly on taste acceptability and in fact on soluble solids to acidity ratio. Juices with the ratio above 17 were usually scored higher concerning the taste than those with lower values. An example of exception was ‘Free Redstar’ which is highly astringent. Considering the efficiency of pressing and soluble solids content several investigated cultivars were highly suitable for concentrated apple juice production. Especially valuable may be considered ‘Regine’, ‘Rebella’, ‘Sawa’, and ‘Topaz’ and can be recommended for planting in industrial orchards, which became of special interest in recent years.

Effect of cold storage on the postharvest quality of different Tarocco sweet orange clonal selections

Fruits of sixteen Tarocco sweet orange (Citrus sinensis [L.] Osbeck) clonal selections were compared for their long-period cold storage aptitude, for fresh fruit consumption. Selections were evaluated, for two consecutive seasons, at harvest (T0) and after 30 (T30), 60 (T60) days of storage at 5 ± 1 °C and 85–90% relative humidity (RH), followed by 7 days of shelf-life at 20±2 °C (T60+7). The following parameters were evaluated: fruit weight, peel and pulp color, initial and residual deformation, elasticity, firmness, juice yield, TSS, pH, TA, total anthocyanin content, and for each control: weight loss and physiological disorders (chilling injury and aging). The selections showed significant variability regarding the physiological disorders, especially at T60+7 with a range of 0.0–0.6 for chilling injury index and a range of values of 0–63% for aging. At T60+7 the weight loss range was between 10.0–14.3%. Regarding overall qualitative parameters, relevant changes were observed for firmness which decreased during the storage, with values ranging from 2.58-5.28 (T0) to 2.56–4.41 (T60+7), and for the anthocyanins which increased from a range of 1.67–39.71 (T0) to 30.47–114.86 mg/L (T60+7), with different values depending on the clonal selections. Based on our results, the clonal selections that showed a better aptitude to long-period cold storage were Gangi, 2B-12–9, Pedalino and Amantea, together with the reference cultivars Meli and Messina. These clones resulted particularly tolerant to chilling injury and aging, they maintained the firmness and the most relevant qualitative traits (TSS and TA) and showed the best fruit external appearance after one week of shelf-life (T60+7).

Effect of cellulase and tannase on yield, ascorbic acid and other physicochemical properties of cashew apple juice

Effect of cellulase and tannase on yield, ascorbic acid and other physicochemical properties of cashew apple juice

Partial rootzone drying and regulated deficit irrigation can be used as water-saving strategies without compromising fruit yield and quality in tropically grown sweet orange

ABSTRACT We examined the effects of partial rootzone drying (PRD) and regulated deficit irrigation (RDI) on some physiological and agronomical traits in tropically grown sweet orange (Citrus sinensis (L.) Osbeck). Seven different irrigation strategies were applied over three consecutive years and compared regarding their effects on leaf gas exchange, vegetative growth, fruit yield and quality and gene expression of fruit quality-related genes. Stomatal conductance and leaf temperature were significantly affected by the different irrigation treatments and seasonal variations in the atmospheric vapour pressure deficit and air temperature. Both PRD treatments (with alternation of the irrigation side every 15 and 30 days) significantly increased the irrigation water use efficiency by 41–56% compared to the full irrigation treatment. RDI treatments induced a significant upregulation of genes related to the citrate metabolism and carotenoid biosynthesis. Trees exposed to PRD with alternation of the irrigation side at every 15 days, as well as to RDI at the fruit ripening stage, showed values of yield, productive efficiency, fruit mass, length and size, juice yield and ratio between soluble solids and titratable acidity similar to those of the full irrigation treatment. Therefore, PRD and RDI can be viable water saving irrigation strategies for sweet orange production in tropical conditions.

Physico-chemical quality and sensory evaluation of pummelo fruit as influenced by potassium fertilization

This study aimed to determine the influence of potassium (K) fertilization on the physico-chemical and sensory qualities of ‘Magallanes’ pummelo [Citrus maxima (Burm. Ex Rumph.) Merr.] fruit. The field experiment was conducted for 12 months at South Davao Corporation (SODACO) farm in Davao City. Five treatments with increasing K levels were applied per tree: control, no K, 150g K basal, 225g K basal, and 225g K basal + foliar application. The fruit physico-chemical qualities and sensory attributes were analyzed the following harvest. Data were analyzed using analysis of variance and honest significance difference tests. Application of 225g K rates positively influenced the fruit quality but not the sensory attributes of pummelo. Fruit pulp diameter increased by 36% while peel thickness decreased by 29-75%. An increase of 39% juice weight per fruit was obtained in 150g K. The yield of juice per tree increased up to 11 times with 225g K level. The 225g K rates also increased juice pH by 8-12%, titrable acidity by 9 times, and total soluble solids per tree by 6 times than no application. The application of 225g K basal + foliar resulted to higher fruit weight, TA, and TSS in pummelo fruit. The results of the study indicated the important role of K in improving the fruit physico-chemical qualities in ‘Magallanes’ pummelo.

Biochemical Characteristics and Antioxidant Properties of Citrus Juice from Lemon (Citrus limon), Lime (Citrus aurantifolia) and Grapefruit (Citrus paradisi) as Influenced by Degree of Ripening

The influence of degree of ripening (unripe, half-ripe and ripe) of citrus fruits (lemon, lime and grapefruit) on the biochemical characteristics and antioxidant potential of their juices was investigated. The juice yield from the citrus fruits was affected by the level of ripening as the highest juice yield was obtained when the fruits were at ripe stage giving 25.2 mL/100 g (lemon), 43.3 mL/100 g (lime), and 21.1 mL/100 g (grapefruit). The biochemical characteristics of the citrus juices revealed that the pH values were generally increasing with an increasing level of ripening particularly for lime and grapefruit while the pH of lemon juice was decreasing with an increase in the degree of ripening. The lowest pH values exhibited by the citrus fruits were 2.87 (ripe lemon), 2.16 (unripe lime), and 3.27 (unripe grapefruits). The total acidity of the citrus juices essentially exhibited an inverse relationship with their corresponding pH values. The highest ascorbic acid contents of the juices were 51.3 g/100mL (unripe lemon), 38.9 g/100mL (unripe lime), and 44.7 g/100mL (unripe grapefruit) while the highest total phenolic contents were 722 µg GAE/mL (unripe lemon), 207 µg GAE/mL (unripe lime), and 646 µg GAE/mL (unripe grapefruit); indicating a significant impact of degree of ripening on the parameters. The antioxidant activity of the citrus juices using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical assay revealed a significant influence of degree of ripening and juice volume on the activity. The percent inhibition of DPPH free radical by the juices was generally higher at an unripe stage of fruit maturity as well at greater juice volume. The ferric-reducing antioxidant potential (FRAP) of the citrus juices was also influenced by the level of ripening of the fruit. The FRAP values were generally higher at unripe stage which were 3.72 µ mol Fe(II)/g (unripe lemon), 4.98 µ mol Fe(II)/g (unripe lime) and 9.53 µmolFe(II)/g (unripe grapefruit).

Assessing Ethanol Yield from Fermented Juice of Local and Exotic Sweet Sorghum Varieties Grown in Sudan

An experiment was conducted in 2017 at Alwaha Project, Khartoum State to study the potential of ethanol yield from fermented juice of local and exotic sweet sorghums. 40 genotypes were arranged in RCB design. Juice yield, ethanol yield as percentage of fermented juice, actual and theoretical ethanol yields were studied. The Baker’s yeast (Saccharomyces cerevisiae) was used in the fermentation process. ANOVA tests, correlation and regression analysis of actual vs theoretical ethanol yield were performed. Significant differences were detected among genotypes for ethanol yields. High ethanol yields as percentage from fermented juice were obtained, but ethanol yield per hectare was relatively low due to low juice yields. The genotypes BlueRibbon and KensasCollies from exotic materials; 5AbjSG51 and S.154 Ab70 from local materials were identified as promising for ethanol production. Correlation between actual ethanol yield and Juice yield was positive and highly significant. Regression analysis indicated that theoretical ethanol yield was little bit overestimated. It was concluded that juice yield is more crucial than ethanol concentration in maximizing ethanol yield of sweet sorghum. More efforts are needed to develop high juice-yielding genotypes. Juice maximization can also be achieved by using efficient milling devices and optimizing cultural practices.

Innovation of Energy Technologies of Food Raw Material Dehydration and Extraction

The researchings of raw material dehydration and extraction are analyzed. The energy problems of product dehydration processes are analyzed. It is shown that recent trends in the development of heat and mass transfer technology are associated with the use of electromagnetic energy generators. The aim of the work is reduction of energy consumption during liquid phase removing from solid plant raw material and reduction of product losses from oil-containing food-industry waste. Achievement of this aim lies with a hypothesis that the use of electromagnetic energy sources in the process of removing moisture from food raw material containing a solid phase will allow to form an additional flow of the liquid phase, in addition to the traditional outlet of the vapor phase. The driving force of such a flow is the effect resulting from the local dissipation of electromagnetic energy in the solid phase volume. A mathematical model of the dehydration process is presented and a set of experimental studies was carried out, which confirmed the validity of the hypothesis. The most significant result of the work is proof of the possibility to organize modes when the juice yield is 4 times higher than the steam yield and, accordingly, to reduce energy consumption for product dehydration. The scientific significance of the obtained results is that a new effect was obtained in the work, which the authors called parodynamic. The practical significance of the work consists of proposing of the technological line for processing oilcontaining waste: coffee sludge, coffee beans husk, reagents (clay and perlite).

НОВЫЕ ТЕХНИЧЕСКИЕ ФОРМЫ ВИНОГРАДА СЕЛЕКЦИИ ВНИИВиВ ДЛЯ ПРОИЗВОДСТВА КРАСНЫХ ВИН

The results of a technological assessment of promising red technical forms of grapes bred by ARRIV&W named after Ya.I. Potapenko are presented. These forms (9-8-2-14pk, 8-7-1-5, 8-5-3-18) are distinguished by high sugar accumulation and optimal juice yield. The re-search was carried out in the laboratory of winemaking technology in micro-winemaking conditions. The mass of one batch of grapes was 5–10 kg, in the wort were determined: titratable acidity, sugar content, pH value, as well as the indicator of technical maturity and glucoacidometric indicator. According to the classical technology, red dry wine materials were prepared. In the studied wine samples the main physicochemical indicators were de-termined. As a result of the organoleptic eval-uation, conclusions were made about the ad-visability of using these forms for the produc-tion of natural red table wines. Augusta was selected as a control variety. Wine materials from the studied varieties were distinguished by their typical, dark ruby color, dense struc-ture and harmonious taste. This indicates a high potential of the studied forms.

Development of the juice extraction equipment: physico-mathematical model of the processes

Multifruit juicers are designed, constructed and improved to be able to process pineapples, oranges and watermelons efficiently. Little juice manufacturers need both a small and efficient device for juice extraction for being economically concurrent compared to big corporations. The authors of the represented paper aim to present the experimental device for juice extraction, its effectiveness, and functional. This device was created using the compressive and compressive shear forces conveyed by an auger conveyor system as a working power. The juicer consists of a hopper, a screw conveyor shaft, a filter screen, a juice outlet, gearbox housing, and a motor. The analysis of the component design enabled the authors to use the data in order to identify the sizes, manufacture and assemble the machine. The authors have made a lot of tests to detect the efficiency and functionality of the presented device. Tests of the device productivity were carried out using watermelons loaded into the device both peeled and unpeeled. Percentage of juice yield, juice extraction efficiency and extraction losses were used as performance indicators. Productivity analysis results revealed that a fruit type and peel condition reliably influenced productivity indicators at the value of 1 %. The percentage of juice yield from peeled and unpeeled watermelons constituted 89.5 % and 89.7 %, respectively. Extraction efficiency constituted 96.6 % for peeled watermelons and 97.1 % for unpeeled ones. Extraction losses amounted to 2.9 % and 2.6 % correspondingly. The proposed device is easy to use and maintain, therefore, it will perfectly suit the needs of small fruit juice manufacturers and can help to get economic efficiency to the small manufacture

Evaluating the physicochemical and antioxidant characteristics of apricot juice prepared through pectinase enzyme-assisted extraction from Halman variety

The investigation aimed at optimizing the process conditions for the enzymatic extraction of apricot juice from Halman variety with pectinase enzyme. The study was conducted at different enzyme concentrations (0.2–1%), temperature (25–50 °C) and time duration (5–375 min). The effects of the enzymatic treatments on selected responses (juice yield, juice clarity, juice turbidity, total soluble solids (TSS), titratable acidity, ascorbic acid content, color index and pectin content) were determined employing a single factor experiment and response surface methodology (RSM) based on central composite rotatable statistical design (CCRD). The treatment effectively hydrolyzed polysaccharides, resulting in increased juice yield, total dissolved solids and juice lightness. The maximum juice recovery (73.06%), total soluble solids (12.9°Brix), clarity (94.76%) and lightness (L*) value (42.85) while minimum turbidity (3.95 NTU) and pectin content (0.59%), were obtained when enzyme treatment was set up with 0.9% w/w enzyme concentration at 44 °C and 300 min. The derived optimum conditions were used for the production of apricot juice of desirable quality in terms of physicochemical and antioxidant properties. Moreover, enzymatic process offers a number of advantages over mechanical-thermal comminution and thus, finds tremendous applications in modern fruit processing industries involving treatment of fruit masses. The process not only facilitates easy pressing and increase in juice recovery but also ensures the highest possible quality of end products.

Using a red‐fleshed and six varieties of thinned young apple to make juice and their phytochemicals characterization

Finding an environmentally friendly way to utilize thinned young apple (TYA) fruits is of great interest in food industry since they were found rich in functional phytochemicals. Making TYA juice is an excellent way but very limited knowledge has been acquired. The juice-making procedures optimization of a red-fleshed and six varieties of TYA fruits were performed with/without steam sterilization before juicing, and the color index, phytochemicals particularly including phenolics and aromas were detailed characterized. Results showed that steaming sterilization of seven TYA were observed conducive to color stability and maintenance, higher sugar contents, comparable acid contents, but lower juice yield and total polyphenol in TYA juices. Moreover, similar polyphenol profiles were detected. Typical 22 aroma compounds were characterized with different profiles and trends in TYA juices. All these findings provide scientific basis for TYA juice making, and demonstrated that TYAs are of great value to develop seasoning juice products. Practical application Fruit thinning is a necessary measure to improve fruit quality in apple production. Thinned young apples can expand the fruit gap through thinning, which is convenient for fruit expansion.The abandoned TYAs in the orchard are posing a risk of environmental pollution, or become host of pathogens to accelerate the spread of fruit diseases. Moreover, discarding the TYAs is a waste of agricultural and food resource since the content of total extractable polyphenols in TYAs is as high as 10 times that in ripe apples. More optimization of processing techniques such as making juice were suggested to improve TYA utilization including the extraction of polyphenols, polysaccharides, and aromas. More food or cosmetics products are expected to be developed based on the TYA juices to improve the commercial value and find an environmentally friendly way to make use of the thinned young fruit.

Bacillus subtilis biofertilizer application reduces chemical fertilization and improves fruit quality in fertigated Tarocco blood orange groves

Rhizobacteria have been used for plant growth promotion of horticultural crops. In this field study, we evaluated the effects of liquid Bacillus subtilis commercial microbial fertilizer (BCMF) on fruit quality and plant nutrient status of fertigated citrus groves of Tarocco blood orange (Citrus sinensis (L.) Osbeck). A total volume of 600 mL BCMF per plant (containing over 2.0 × 108 colony-forming units (CFU)mL−1) was applied by diluted to 15 L through an integrated water and fertilizer irrigation system after the schedule of conventional fertilization (CF) of 100 % (CF100 + BCMF) and 50 % (CF50 + BCMF), and 15 L of clean water were used for irrigation after 100 % CF as the control treatments (CK). Both BCMF applications had positive correlation with fruit internal quality parameters, such as fruit maturity index (FMI), juice yield, edible rate, and per fruit weight (PFW), along with improved fibrous root density. However, the application of CF100 + BCMF delayed fruit peel and pulp coloring, and the highest nutrition partition ratio from soil to leaf of N (NNPRsl) and K (KNPRsl) and leaf nutrients concentration of N and K during harvest stage were achieved. In contrast, the CF50 + BCMF treatment led to a simultaneous color change in the fruit peel and the pulp along with a lower NNPRsl during the early stage of fruit ripening and leaf K concentration during fruit ripening due to the reduction of chemical fertilizer application as compared with the CK treatment. Meanwhile, the BCMF applications increased soil available P content and caused fruit titratable acids (TA) reduction. Our results suggest that the influence of B. subtilis biofertilizer application on fruit quality depends on the amount of the chemical fertilizers used, the application of biofertilizers contributes to reducing fertilizer input and exerts positive effects on the fruit quality in fertigated Tarocco blood orange groves.

Development and research of new method for juice extracting from sugar beet with preliminary pressing

The main objectives of the experimental studies were to obtain kinetic patterns and to determine the rational parameters of the pressing processes, ensuring high efficiency of the process of juice obtaining from sugar beets by the press method. The main indicator of the pressing process effectiveness is the yield of beet juice pressed (extruded) in the press, since the parameters of the further production process depend to a large extent on it. In accordance with this, one of the experimental studies aims was to maximize the beet juice yield. To do this, a series of experiments was carried out. Their results made it possible to determine the degree of various factors influence on the juice yield. However, striving for the maximum beet juice yield, it should be taken into account that the resulting juice should be of the highest quality, which would ensure the possibility of its further effective purification. Therefore, in addition to the juice yield, another objective of the experiments was to determine the factors affecting its quality. The total effectiveness of the technology developed will be the result of an optimal combination of the juice extraction value and its quality indicators.

The quality assessment of raw materials for the production of functional juice drinks

The present work is aimed at studying the qualitative characteristics of apple fruits growing in the Baikal region and evaluates their technological parameters. The main physicochemical parameters and the total content of phenolic compounds in juice of seven apple breeds are investigated. All fruits were small, their weight varied from 20g (Pepinchik Krasnoyarskiy) to 80 g (Svetloe), the average weight was 40 g (Krasnaya Grozd). The highest juice yield was shown by the variety with the average size (Krasnoyarsk’s Snegirek–71.8 %), the remaining varieties showed about 60 %. The sugar content of fruits varied from 5 to 12.3 g / 100 cm3 in varieties, and the amount of titrated acid (in terms of malic acid) from 4.8 to 10.8 g / dm3. For the fruits of seven varieties the content of macro- and microelements (Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Zr, Pb and Ba) was analysed by X-ray fluorescence spectrometry. Total phenolic compounds content as well as content of anthocyans and leucoanthocyanin were identified in juice. The content of phenolic substances in juice varied (g / dm3) from 3.6 (Krasnaya Grozd) to 0.3 (Krasnoyarskiy Pepinchik). Qualitative and quantitative composition of the main components of the studied juice shows the feasibility of using the fruits of local apple breeds for the production of functional juice-containing drinks.

Study the Effect of Pectase on Juice Yield of Rubus corchorifolius

The experiment of effect of pectase on juice yield of raspberry were studied in quantity, reaction temperature and time of enzymolysis through single factor and orthogonal experiments in this paper. The optimum conditions were as followed: pectase content 0.07%, temperature 45°C, enzymatic enzymolysis time 3.5h and under these conditions the juice of pectase contain its active ingredient greatly.

Main Agro-Morphological and Biochemical Berry Characteristics of Wild-Grown Sea Buckthorn (Hippophae rhamnoides L. ssp. caucasica Rousi) Genotypes in Turkey

Sea buckthorn (Hippophae rhamnoides L. ssp. caucasica Rousi) is one of the most important wild edible fruits, grown in Turkey for centuries without any chemical treatments. The plant is extremely resistant to adverse environmental conditions. In this study, the main agro-morphological and biochemical berry traits and, to a lesser extent, other plant morphological traits of 10 sea buckthorn genotypes sampled from the eastern Anatolia (Sivas province) region were assessed. Among the 10 genotypes, five of them presented a shrub growth habit, whereas five of them presented tree growth habit, with leaf area ranging from 2.56 to 4.22 cm2. The majority of genotypes had an oblong berry shape with variable berry skin color ranging from dark orange to orange, light orange, and yellow. The weight of 100 berries varied from 13.85 to 23.87 g, while juice yield and vitamin C content was found to be 44.87–57.15% and 37.45–62.85 mg/100 g fresh berry base, respectively. Soluble solid content (SSC) was in the range of 12.56–14.67%. The genotypes exhibited a great variability in total anthocyanin content (from 9.1 to 38.7 mg/L), with relatively dark-orange sea buckthorn berries containing more anthocyanin than orange, light-orange, and yellow berries. Linoleic acid was the main fatty acid detected in the pulp of sea buckthorn berries, ranging from 24.11% to 36.37%, depending on the genotype. Investigated genotypes proved also to be rich in total phenolic content, showing at the same time great variability in this trait. The results obtained from the relatively limited number of genotypes show promising traits for further valorization of both horticultural and nutritional traits, suggesting potentially even higher variability, if more genotypes are going to be considered in the future.

Multi-criteria optimization of beet juice obtaining process by press-diffusion method

Currently, the application of advanced technologies in sugar factories is relevant. These technologies are based on the use of a combination of physical and energy effects on the feedstock and provide a reduction in sucrose losses at the stage of diffusion juice obtaining. A method of press-diffusion production of juice from sugar beet which allows to increase the yield of sucrose from beet chips and to reduce losses at the stage of diffusion juice obtaining and production costs is suggested by us. The press-diffusion method of extracting juice from sugar beet with the methods of mathematical planning and statistical processing of the experimental results was studied in the work. Regression equations and suboptimal parameters providing the maximum yield of beet juice with minimum energy consumption for its implementation were received in experimental plants under the influence of technological parameters, which were the pressure applied to the beet mass at the pressing stage, the temperature at the diffusion stage, and the pretreatment temperature of beet chips before pressing and the frequency of ultrasonic vibrations of the emitter in the diffusion installation. These operating parameters were the following: pressing pressure 0.27–0.33 MPa, pretreatment temperature of beet chips 334.2–337.3 K, diffusion temperature 342.5–345.0 K and frequency of ultrasonic radiation 21.25–23.36 kHz. The engineering nomograms presented make it possible to determine the value of the specific energy consumption and the value of the liquid phase output from the technological parameters of the press-diffusion method for producing beet juice in a quick and qualitative way.

Effects of ultrasound on the enzymatic degradation of pectin

Ultrasound-assisted enzymatic maceration (UAEM) has gained considerable interest in the fruit juice industry, owing to its potential to increase juice yield and content of polyphenols while simultaneously saving time and energy. In this study, the effects of UAEM (ultrasonic probe, 20 kHz, 21 W*cm−2 and 33 W*cm−2) on pectin degradation in a continuous circulation system were investigated over 60 and 90 min. Main pectinolytic enzymes activities of (polygalacturonase, pectin lyase and pectin methylesterase) of a commercial enzyme preparation were examined for individual synergistic effects with US. Pectin hydrolysis by UAEM differed significantly compared to treatment with ultrasound or enzymes alone regarding the profile of degradation products compared to treatment with ultrasound or enzymes alone. Ultrasound fragmented pectin to less branched oligomers of medium molecular weight (Mp approx. 150 kDa), which were further degraded by pectinolytic activities. The low molecular weight fraction (<30 kDa), which is known to be beneficial for juice-quality by adding nutritional value and stabilizing polyphenols, was enriched in small oligomers of homogalacturonan-derived, rhamnogalacturonan I-derived, and rhamnogalacturonan II-derived residues. Synergistic effects of ultrasound application enhanced the effective activities of polygalacturonase and pectin lyase and even prolonged their performance over 90 min, whereas the effective activity of pectin methylesterase was not affected. Final marker concentrations determined by each enzyme assay revealed a considerable higher total process output after UAEM treatment at reduced temperature (30 °C) comparable to the output after conventional batch maceration at 50 °C. The obtained results demonstrate the high potential of UAEM to produce high-quality juice by controlling pectin degradation while reducing process temperature and equally highlight the matrix and enzyme specific effects of a simultaneous US treatment.