The effect of pre-treatment on the anthocyanin and flavonol content of black currant juice (Ribes nigrum L.) in concentration by reverse osmosis

Reverse osmosis process for the concentration of black currant juice was carried using AFC-99 tubular membrane at 30 °C and 45 bar. The contents of selected flavonols and anthocyanins were analyzed after centrifugation; enzyme treatment by Panzym Super E and by Rohapect berry followed by centrifugation; and ultrafiltration black currant juices and juice concentrates. The total soluble solid (TSS) content of the juices increased from the initial 17.6–17.9 °Brix to 24–24.8 °Brix in the case of the centrifuged juice in the concentration process. Similarly, it increased from 14.5–15.5 °Brix to 23.1–23.4 °Brix for the Panzym Super E treated juice, and from 16.1–16.9 °Brix to 22.5–23.1 °Brix for the Rohapect berry treated black currant juices. The ultrafiltered juice had the lowest initial TSS content between 14.1 and 14.9 °Brix and it increased to 22.1–23.1 °Brix. The average permeate fluxes during the concentration process were 7.3 L m⁻² h⁻¹ for the centrifuged juice, 11.9 L m⁻² h⁻¹ for the Panzym Super E treated juice, 9.2 and 13.1 L m⁻² h⁻¹ for the Rohapect berry treated and ultrafiltered juice, respectively. Analysis indicated that the enzymatic treatment resulted in the increase of anthocyanin and flavonol content of the juices. The centrifugation process decreased the amount of anthocyanins and flavonols to some extent. The juice clarified by ultrafiltration had significantly lower concentrations of anthocyanins and flavonols, while the juices treated by Panzym Super E had the highest levels of these flavonoids. This study recommends enzymatic pre-treatment by Panzym Super E, since it improves the permeate flux in reverse osmosis during the concentration process, and results in a juice concentrates highest in anthocyanins and flavonols.     

Rheological properties of ultraviolet-irradiated and thermally pasteurized Yankee pineapple juice

The rheological behaviour of Yankee pineapple juice was examined for the effect of ultraviolet (UV) irradiation (53.42 mJ/cm²) and compared with untreated juice and a thermally pasteurized (80 °C for 10 min) juice. A rheological test was performed on all types of juice in the temperature range 5 °C to 25 °C using a concentric cylinder rheometer at a shear rate range of 10–290 s⁻¹. The comparative analysis found that the best flow curves were described by the Bingham model with an initial shear stress. The entangled pulps in the juices prevented free flow at zero shear rate. There was no significant variation between the plastic viscosities of the untreated and UV-irradiated juice at all temperatures. The activation energy (E_a) of the untreated, UV-irradiated and thermally pasteurized juice was 6.80, 8.19 and 8.50 kJ/mol respectively.     

Processing and protein-fractionation characteristics of different polymeric membranes during filtration of skim milk at refrigeration temperatures

Serum protein concentrates (SPCs) were generated from reconstituted skim milk (3.2% protein) using lab-scale tangential-flow filtration at 3–4 °C. The influence of membrane type on process performance (e.g., permeate flux) and protein-enrichment (e.g., protein profile) was assessed with polyvinylidene-difluoride membranes (0.1 μm and 0.45 μm pore-size), and a polyethersulfone membrane (1000 kDa cut-off). The 1000 kDa membrane exhibited the highest starting flux (6.7 L m⁻² h⁻¹), followed by the 0.1 μm (5.4 L m⁻² h⁻¹) and 0.45 μm (4.8 L m⁻² h⁻¹) membranes. Flux decreased by >40% during filtration with the 1000 kDa and 0.1 μm membranes, while the decrease was lower (<20%) with the 0.45 μm membrane. β-Casein comprised >97% of casein in SPCs from the 0.1 μm and 1000 kDa membranes. SPCs from the 0.45 μm membrane had higher β-casein:α_s-casein ratios than the feed and higher levels of minor whey proteins (e.g., lactoferrin) relative to the other SPCs.     

Quality changes in cold pressed juices after processing by high hydrostatic pressure,ultraviolet-c light and thermal treatment at commercial regimes

The quality, nutritional and organoleptic parameters of cold-pressed lemonade, citrus and green juice were assessed following commercial HPP (600 MPa/3 min), UV-C light (253.7 nm/1000 L h⁻¹/411.4 mJ cm⁻²) and thermal treatment (75 °C/90 s) using processing regimes currently accepted in the beverage industry. Although the treatments did not affect pH, soluble solids and viscosity, they affected colour with the most pronounced change occurring in the green juice following thermal treatment. Overall, the treatments resulted in good retention (< 25% reduction) of ascorbic acid, total phenolic and antioxidant content. Notable exceptions included thermal and overdosed UV-C treatments (> 90% reduction of ascorbic acid in lemonade). HPP treatment had a neutral or positive effect on consumer acceptance of all juices, whereas thermal and overdosed UV-C treatments caused undesirable sensory changes to green and citrus juices, respectively. Overall, thermal treatment and UV-C light induced chemical changes that differentiated treated juice from the raw sample.Industrial relevanceThis study verified that the currently accepted processing regimes for commercial scale HPP, UV-C light and thermal treatment affected colour, nutritional, chemical and/or sensory properties depending on the beverage matrix, suggesting that an individual product treatment approach is required for each juice. In the case of UV-C light, the effectiveness of the treatment was influenced by juice composition and UV transmission as well as the fluence level. Overdosed UV-C treatment was shown to cause undesirable effects on juice nutritional parameters. Hence, further optimization of commercial processing regimes and studies evaluating the suitability of each technology on a case by case basis should be considered.     

Edible films produced from agrifood by-products and wastes

This study aims to develop edible films using agrifood by-products (pumpkin seeds, broken rice and orange pectin) and wastes (quince peel, potato peel, potato pulp, orange peel, pumpkin peel). The physicochemical characteristics of the films were investigated, including their mechanical and barrier properties. Higher amounts of plasticizer induced poorer mechanical and barrier properties in the films. The most promising ones were obtained with orange pectin, broken rice and pumpkin peel, with water contact angles (WCA) between 48° and 57°, maximum water vapor transmission rate and water vapor permeability of 575 g.m⁻².d⁻¹ and 108 × 10⁻¹² g.Pa⁻¹.s⁻¹.m⁻¹, respectively, Young's modulus between 350 and 800 MPa, maximum tensile strength between 9.0 and 26.25 MPa, and elongation at break between 2.28 and 9.3%. Orange pectin and broken rice are promising raw materials since they led to higher WCA, better barrier and mechanical properties. Broken rice and quince peel can be good substitutes for commercial starch and glycerol, respectively. Agro-industrial by-products and wastes revealed potential for the production of sustainable edible films.     

Better lime purification of sugar beet juice obtained by low temperature aqueous extraction assisted by pulsed electric field

Purification of the sugar beet juices obtained by novel low temperature extraction (at 30 °C) assisted by pulsed electric field (PEF) and conventional high temperature extraction (at 70 °C) was done by the method of lime-carbon dioxide treatment. The total concentration of lime used for the purification was varied from 6 to 15 kg of CaO/m³ of the juice. Filtration properties of the juices of first carbonation, as well as purity and coloration of the final thin juices, were compared. It was observed that purification of the juice extracted at 30 °C results in faster filtration of the juice of first carbonation and lower coloration of the final thin juice as compared to the juice obtained by means of purification of the juice extracted at 70 °C. It suggests that the quantity of CaO required for the efficient juice purification may be decreased from 15 kg/m³ (for the juice extracted at 70 °C without PEF treatment) to approx. 8 kg/m³ (for the juice obtained by PEF-assisted extraction at 30 °C).     

Watermelon juice pretreatment with microfiltration process for obtaining lycopene

The aim of this study was to evaluate the effect of microfiltration on the lycopene content and antioxidant capacity of watermelon juice using ceramic membranes with an average pore size of 0.1 μm and a permeable area of 0.022 m². The influence of the tangential cross‐flow velocity (4.3–6.4 m s^?1) and temperature (23–37 °C) on the permeation flux, lycopene content and antioxidant capacity was evaluated. A 2² complete factorial experimental design was used. Increases in tangential cross‐flow velocity and temperature had positive effects on permeation flux, with a maximum of 92.4 l h^?1 m^?2 achieved at 6.4 m s^?1 and 30 °C. With regard to the lycopene content and antioxidant capacity, tangential cross‐flow velocity was the only factor that exhibited significant effects on these responses. For the most concentrated extract, the lycopene concentration and antioxidant capacity were enhanced by 402.8% and 416.3%, respectively.     

Essential oil nanoemulsions: antibacterial activity in contaminated fruit juices

Many human acid tolerant bacterial and fungal pathogens can be transmitted through the consumption of the contaminated fruit juices. We aim to formulate essential oil nanoemulsions (basil, black seed, turmeric, clove & cinnamon), determine their ability to clear contamination by food borne bacterial pathogens from fruit juices. The antibacterial activity of the optimised formulations was tested in the fruit juices against bacterial pathogens causing gastrointestinal tract infections. The minimum bactericidal concentration (MBC) of clove emulsions ranged from 15.6 to 25 μL mL⁻¹. Cinnamon oil emulsion had an MBC ranging between 15 and 31 μL mL⁻¹. At MBC, cinnamon oil emulsions caused a 6log₁₀ decrease in viable counts by 8 h and maintained the sterility of fruit juices for 7 days at ambient temperature. Thus, clove and cinnamon microemulsions can be used as juice additives to control food borne bacterial pathogens and maintain the bacterial sterility of fruit juices.     

UV-C irradiation as an alternative disinfection technique: Study of its effect on polyphenols and antioxidant activity of apple juice

Ultraviolet (UV-C) irradiation is a non-thermal disinfection method, effective against a range of bacteria and viruses, which is being considered as an alternative to pasteurization of fruit juices. The objective of this study was to investigate the effect of UV-C irradiation on the polyphenolic content and in-vitro total antioxidant activity of apple juice. UV irradiation doses ranging from 0 to 240 mJ·cm^− 2 were delivered to apple juice and polyphenols, sugars, in-vitro total antioxidant activity and total phenols were profiled. The results demonstrated that UV-C irradiation in apple juices at relevant commercial disinfection doses induced significant reduction in the concentrations of chlorogenic acid, phloridzin, and epicatechin (p < 0.05). The induced changes were relatively minor for the above mentioned polyphenols, except phloridzin (50% reduction) at 240 mJ·cm^− 2. Epicatechin concentrations were reduced significantly (p < 0.05), whereas increase in catechin concentration was observed with increase in UV-C exposure to 240 mJ·cm^− 2. There was a minor reduction in sugar (glucose and fructose) concentrations with increasing exposure levels from 0 to 40 mJ·cm^− 2 (p > 0.05). In contrast, a slight increase in sugar concentrations as increase in UV-C exposure after 40 mJ·cm^− 2 was observed. These changes were not significantly different from control. Total phenolic content was well retained regardless of the UV-C exposure for apple juice. In-vitro total antioxidant activity changed when UV-C exposure exceeded 40 mJ·cm^− 2, but remained unchanged at the maximum UV-C dose of 240 mJ·cm^− 2. These results suggested that UV-C irradiation could be an effective alternative to conventional thermal processing for production of high quality apple juice.Industrial RelevanceThis research paper provides scientific evidence of the potential for UV-C irradiation to achieve meaningful levels of disinfection while retaining important bioactive compounds (polyphenols) in apple juice. In-vitro antioxidant activity and individual polyphenols were well retained at commercially relevant doses of 40 mJ·cm^− 2. From a nutritional perspective, UV-C irradiation is an attractive food preservation technology and offers opportunities for horticultural and food processing industries to meet the growing demand from consumers for healthier food products. Therefore, UV-C irradiated foods could be sold at a premium price to their thermally-processed counterparts, as they have retained their fresh-like properties. This study would provide technical information relevant for commercialization of UV-C treatment of juices.     

Quality and filtration characteristics of sugar beet juice obtained by “cold” extraction assisted by pulsed electric field

Detailed comparison of various properties (concentration of soluble solids, purity, nature of impurities, coloration and filterability) of sugar beet juices obtained by pulsed electric field (PEF) assisted “cold” extraction (T = 30 and 50 °C) and classical “hot” extraction (T = 70 °C) was done. It was shown that application of PEF-assisted “cold” extraction results in lower concentration of colloidal impurities (especially, pectins), lower coloration and better filterability of juice. Concentration of various colorants and their intermediates decreased significantly with decreasing of the extraction temperature from 70 °C to 30 °C. Filtrate obtained by dynamic filtration of juice extracted with PEF treatment had a high purity (95.3 ± 0.4%) and low coloration (1.2×10³ IU). Obtained data suggest that PEF-assisted “cold” extraction is a promising method for preparation of sugar beet juices with high purity.     

Assessing the acid tolerance and the technological robustness of probiotic cultures for fortification in fruit juices

The suitability of probiotic cultures as fruit juice supplements was examined by assessing their acid tolerance and technological robustness. Survival of Lactobacillus and Bifidobacterium strains in orange juice (OJ), pineapple juice (PJ) and cranberry juice (CJ) was monitored. Results revealed that extensive differences exist among probiotic strains regarding their acid resistance. All of the strains screened survived for longer in OJ and PJ compared to CJ. L. casei DN-114 001, L. rhamnosus GG and L. paracasei NFBC43338 displayed the greatest robustness surviving at levels above 10⁷ cfu ml^− 1 in OJ and above 10⁶ cfu ml^− 1 in PJ for at least 12 weeks. Probiotic tolerance to thermal and non-thermal processing was studied to determine the feasibility of their addition to OJ prior to pasteurisation. OJ fortified with probiotic cultures was subjected thermal pasteurisation at 76 °C for 30 s and 90 °C for 1 min in addition to a high pressure treatment of 400 MPa for 5 min. Results indicated no strain was capable of withstanding treatments necessary to achieve a stable juice at levels > 10⁶ cfu ml^− 1. The outcome of the overall study points to L. rhamnosus GG, L. casei DN-114 001 and L. paracasei NFBC43338 as having promising potential for exploitation as functional supplements in fruit juices due to their impressive tolerance in acidic environments; however, fortification post processing is recommended.Industrial relevanceThe ability of health-promoting cultures to survive for at least 12 weeks in orange juice and pineapple juice at commercially critical levels renders them suitable strains for exploitation. Their inclusion may enhance the market potential of these already successful beverages.     

Flavanone glycosides in Brazilian orange juice

Authentic samples of oranges, frozen concentrated orange juice and pulp-wash, and retail samples of freshly squeezed orange juice and frozen concentrated orange juice have been collected in Brazil and analysed for the flavanone glycosides (FG) narirutin and hesperidin by reversed phase HPLC with UV detection at 280 nm. The juice from hand-squeezed fruit gave narirutin and hesperidin concentrations of 16–142 mg l⁻¹ and 104–537 mg l⁻¹, respectively. The ratio of hesperidin to narirutin showed varietal difference with Pera having the highest ratio (mean 8.4) and Baı́a the lowest (3.6). Frozen concentrated orange juice contained higher quantities of FG with narirutin ranging from 62 to 84 mg l⁻¹ and hesperidin from 531 to 690 mg l⁻¹ (after dilution to 12 °Brix). In frozen concentrated orange juice pulp-wash, the narirutin level ranged from 155 to 239 mg l⁻¹ and hesperidin from 1089 to 1200 mg l⁻¹. The analysis of 23 samples of freshly squeezed juice from the Brazilian market place showed that the FG content of most samples (9.1 to 94.8 and 105.8 to 586.6 mg l⁻¹, respectively, for narirutin and hesperidin) was similar to those found for authentic ones, indicating that these orange juices were not adulterated.     

Application of simulation in determining suitable operating parameters for industrial scale fluidized bed dryer during drying of high impurity moist paddy

A systematic approach has been developed for selecting the suitable drying parameters to be used for drying of high moisture and high impurity paddy with an industrial fluidized bed paddy dryer (10–20 t h⁻¹ capacity) based on targeted specific air flow rate and residence time during two typical paddy drying seasons. A mathematical model was developed by modifying an existing model and was simulated and validated with observed industrial drying data as well as data reported in the literature. Comparison between the observed and simulated results showed that the mathematical model is capable of predicting outlet paddy moisture content and air temperature well. Suitable operating parameters were determined for reducing any initial paddy moisture content (mc) down to 24–25% dry basis (db), the safe mc level after fluidized bed drying to maintain rice quality, to achieve maximum possible throughput capacity of the dryer with corresponding energy consumption. Based on these criteria, bed thickness at 10 cm, specific air flow rate of 0.05 kg kg⁻¹ s⁻¹ (for corresponding bed air velocity of 2.3 m s⁻¹), air temperature of 150 °C and residence time of 1.0 min were found to be suitable drying conditions for reducing paddy mc from 30 to 24.30% (db) in one season while the maximum throughput capacity of 15.7 tonne per hour (t h⁻¹) might be achieved. The specific electrical and thermal energy were 0.48 and 6.15 MJ kg⁻¹ water evaporated, respectively. On the other hand, the dryer capacity was found to be limited to 7.4 t h⁻¹ during drying paddy of higher initial mc (35% db). This approach might provide easy and comprehensive guidelines for selecting suitable sets of operating parameters for any industrial fluidized bed dryer at its possible maximum throughput capacity for drying of freshly harvested high moist paddy with a high level of impurities.     

Hydrodynamic cavitation: Process opportunities for ice-cream formulations

We report the viability of hydrodynamic cavitation (HC, 2400–3600 RPM/100–200 L h⁻¹) to manufacture ice-cream with reduced stabilizer. The study was carried out at a pilot-scale level and consisted of determining the impact on particle size and rheological behavior of ice-cream mixes (ICM) and evaluating the resulting melting and meltdown behavior of ice-cream. Ice-cream manufactured with two-stage homogenization (2500/500 psi) was used as a control treatment. Overall, HC resulted in a larger mean particle size than the control mixes (3.52 ± 0.28 and 0.34 ± 0.02 μm, respectively). Additionally, HC (3600 RPM/100 L h⁻¹) changed the flow behavior of ICM from viscoelastic solid to viscoelastic liquid. Cavitated mixes resulted in a 2.2-fold viscosity increment within the high spectrum of shear rate (30–50 s⁻¹) compared with the control mixes. These modifications altered the melting and meltdown characteristics of the resulting ice-cream. The analysis of the particle size and gross microstructure of dripped melted ice-creams suggested a significant collapse of the ice-cream structure, allowing clumps of fat to migrate into the melted phase. This study showed that HC might have the potential to develop novel structures for frozen desserts.     

Concentrates from citrus juice obtained by crossflow microfiltration: Guidance of the process considering carotenoid bioaccessibility

This work focused on an eco-friendly process to concentrate carotenoids from a citrus juice formulated with clementine and pink grapefruit. It is based on crossflow microfiltration associated with enzymatic liquefaction, diafiltration and pasteurization. The aim was to evaluate the impact of the main operating conditions on the process performance and on the nutritional quality of the final concentrate taking into account the bioaccessibility of β-carotene, β-cryptoxanthin and lycopene. First, the best enzyme/pressure/membrane combination was chosen in order to maximize permeate flux during microfiltration (>100 kg.h⁻¹.m⁻² at 2.6 bar with tubular inorganic membranes). Second thanks to a Plackett-Burman experimental design applied to the whole process, we showed the enzymatic dose was the most impacting parameter on carotenoid bioaccessibility and it decreased it. An optimal dose of enzyme had to be defined in order to obtain a good compromise between the process performance and the nutritional quality of the citrus concentrate.     

Antioxidant capacity,phenolic composition and microbial stability of aronia juice subjected to high hydrostatic pressure processing

The aim of this study was to characterize the effect of high hydrostatic pressure (200–600 MPa/15 min) and storage (4 °C/80 days) on aronia juice quality. The total antioxidant capacity, phenolic content and composition were assessed using an updated analytical strategy. Microbial growth was also analyzed following juice storage. Among all the analyzed juices, the untreated aronia juice had the greatest reduction (36%) in total polyphenols over the entire storage period. At the end of the storage period, the pressurized juices demonstrated ABTS and FRAP values higher by 14% and 5% as compared to the untreated juices. The main antioxidants identified in the aronia juice were: chlorogenic acid; neochlorogenic acid; cyanidin 3-galactoside; cyanidin 3-xyloside; cyanidin 3-arabinoside; cyanidin 3-glucoside. Cyanidin 3-glucoside was the most stable compound during juice storage. Microorganism growth in juices pressurized at 400–600 MPa was below the detection limit (< 1 CFU mL^− 1) upon storage.Industrial relevanceAronia berries are rarely consumed fresh since they give off several negative sensory attributes. Multiple health-promoting properties of aronia berries make them a valuable raw material for juice production. However, processing involves pasteurization or hot-filling strongly diminishes the product quality due to the changes in quantity and quality of thermolabile phytochemicals. The objective of this work was to characterize the effect of high hydrostatic pressure on the antioxidant capacity, polyphenol content and composition and microbial stability of aronia juice. Results of this study may be useful for the juice industry commercialize this technology for the development healthy, nonclarified aronia juices with desired level of quality.     

Supercritical fluid extrusion: Die design and physicochemical properties of milk protein extrudates

Extrusion processing has been used to modify the functional properties of proteins. The protein-protein interactions, surface hydrophobicity, and rheological properties of milk protein concentrate extruded using dies of different geometries (circular, annular and slit) were quantified. With the same extrusion treatment history prior to the die, extrudates generated using dies with higher wall shear (slit 1.4 × 10⁴ s⁻¹ > annular 1.1 × 10⁴ s⁻¹ > circular 2.9 × 10³ s⁻¹) showed greater protein extractability, higher index of surface hydrophobicity, and enhanced water solubility index indicating significant breakdown of protein aggregates. Higher viscoelastic moduli (G' and G") and apparent viscosity were observed for slit die extrudate dispersions. However, low flow behavior indices (0.04–0.23(−)) and a high viscous activation energy (43 kJ/mol) of slit die extrudate dispersions implied their shear and temperature sensitivity, respectively. Thus, extrudate functionality can be optimized by selection of the appropriate die design.     

Dead end ultra-filtration of sugar beet juice expressed from cold electrically pre-treated slices: Effect of membrane polymer on fouling mechanism and permeate quality

Purification of raw sugar beet juice expressed at ambient temperature (20 °C) from pretreated sugar beet slices by pulsed electric field (E = 600 V·cm^− 1, t_PEF = 10 ms, T = 20 °C) was studied on the laboratory scale by dead-end ultrafiltration tests. Polyethersulfone (PES) and Regenerated Cellulose (RC) membranes with the same nominal molecular weight cut-off of 30 kDa were used. Experiments were carried out in unstirred and stirred (at rotation speed of 500 rpm) mode at constant trans-membrane pressure of 2 bar. The effects of the membrane polymer (Polyethersulfone and Regenerate Cellulose) on the filtration flux and the permeate quality were studied. In order to identify the fouling mechanism, the filtration kinetics was modeled using combined fouling models. Results showed that the filtration productivity (filtration flux) and selectivity (rejection ratio of impurities) depended on the membrane polymer. The juice filterability was better with Regenerated Cellulose (RC) membrane while the polyethersulfone (PES) membrane ensured a better retention of impurities (colorants, proteins and colloids), leading to a higher juice purity. Experimental and models data adjustment showed that combined models were preferable to investigate the fouling mechanism for both unstirred and stirred filtration. The desirable sugar purity (95–96%) of filtrate implies the potential application of a novel process (PEF treatment-cold pressing-ultrafiltration) for sugar industrial production.Industrial relevancePre-treatment by pulsed electric field PEF allowed cold or mild extraction of sucrose from sugar beet roots. The combination of PEF and ultra-filtration allowed high yield sucrose extraction and purification with less energy consumption. Membrane fouling analysis led to better filtration producibility. The obtained data can be useful for optimization of the sucrose production with high yield in industrial extraction processes.     

Measurement techniques for steady shear viscosity of Mozzarella-type cheeses at high shear rates and high temperature

While measuring steady shear viscosity of Mozzarella-type cheeses in a rotational rheometer at 70 °C, three main difficulties were encountered; wall slip, structural failure during measurement and viscoelastic time dependent effects. Serrated plates were the most successful surface modification at eliminating wall slip. However, even with serrated plates shear banding occurred at higher shear rates. Because of the viscoelastic nature of the cheeses, a time dependent viscous response occurred at shear rates <1 s⁻¹, requiring longer times to attain steady shear conditions. Prolonged continuous shearing altered the structure of the molten cheeses. The effects of structural change were greatly reduced by minimising the total accumulated strain exerted on the sample during flow curve determination. These techniques enabled successful measurement of steady shear viscosity of molten Mozzarella-type cheeses at 70 °C at shear rates up to 250 s⁻¹.     

Influence of processing steps and fruit maturity on volatile concentrations in juices from clementine, mandarin, and their hybrids

During growth, ripening, and post-harvest, the quality of fruits can be modified by various stresses. Ample maturation allows prolonged storage and increases the quality of citrus fruits. The eight major volatile compounds in fresh juices from mandarin (Citrus reticulata Blanco var. Willow Leaf), clementine (Citrus reticulata × Citrus sinensis var. Commune), and their six cross-pollinated hybrids were quantified by gas chromatography. Mandarin juice contained the highest volatile concentration (2177.6 ± 110.6 mg L⁻¹), whereas the total aromatic compounds of the hybrid and clementine juices were lower (1060.6 ± 81.6–1724.2 ± 138.5 mg L⁻¹ and 864.8 ± 67.8 mg L⁻¹, respectively). Limonene was the major compound (667.3 ± 53.7–1259.9 ± 98.4 mg L⁻¹) in all juices. We observed significant differences according to the process of juice extraction used (with and without peel). The relative volatile concentration was higher when the juice was extracted with peel, and the juicing process induced differences in the relative volatile concentrations of between 20 and 40%. The levels of volatile compounds in the juice changed according to the degree of fruit maturity. The concentrations of the eight major juice components increased during ripening and until the commercial maturity stage when the juice was obtained from peeled fruits, whereas their concentrations increased until the post-maturation stage when the juices were produced from whole fruits. These two factors determined the contributions of these compounds to the characteristic aromas of Citrus juices.