Effect of particle size on the stability and flavor of cloudy apple juice

Investigating the influence of insoluble pulp particles on flavor retention and characterization of freshly squeezed and pasteurized mandarin juice

The presence of insoluble pulp particles influences flavor release and aroma characteristics in citrus juice. This study aimed to investigate the distribution of volatiles in both the liquid and insoluble pulp particle phases of freshly squeezed and heated mandarin juice. Two methods fiber-solid phase microextraction (SPME) and thin film (TF)-SPME, were employed to extract volatiles, which were then analyzed via gas chromatography-mass spectrometry (GC-MS) and a thermal desorption unit-cold injection system 4-multidimensional GC-MS/olfactometry (TDU-CIS4-MDGC-MS/O) with time-intensity. A total of 95 volatiles, including 31 odorants, were identified. Notably, methional was the only volatile sulfur compound detected in different sizes of insoluble pulp particles. More volatile varieties were found in the liquid phase (48-65) than in the insoluble pulp particles (37-45), and larger insoluble pulp particles retained more volatiles. The volatile content of heated insoluble pulp particles was 1.43-20.63 times greater than that of the corresponding fresh pulp particles, mainly due to hydrocarbon retention. Pasteurization enhanced aroma compound retention in insoluble pulp particles, especially hydrocarbons (α-terpinene and terpinolene) and ketones (geranylacetone). With increasing centrifugation intensity, the aroma intensity of off-flavor dimethyl sulfide and methional increased in freshly squeezed mandarin serum, that of carbon disulfide increased, that of dimethyl sulfide decreased in heated mandarin serum, and that of methional decreased in insoluble pulp particles. In conclusion, insoluble pulp particles significantly impact the flavor of mandarin juice. Six and four potential markers were identified to distinguish flavor differences between freshly squeezed and heat-sterilized liquid phase or insoluble particle samples, respectively.

Deciphering structure-rheological properties relationship via the studies of 11 s-rich and 7 s-rich soy protein isolate

Rheological properties influence the velocity gradient in the die passage of the extruder and the formation of fibrous structure of plant protein. The rheological properties of 11 s-rich (11 s-RI) and 7 s-rich (7 s-RI) soy protein fractions prepared at a pilot scale were studied to explore their potential in the production of extruded textured proteins. The results showed that compared to 7 s-RI, 11 s-RI exhibited larger particle sizes, lower solubility, lower water holding capacity of insoluble protein, and lower net surface charge in aqueous solutions. The ion strength enhancement with the presence of phosphate resulted in increasing solubility of 11 s-RI, and rising particles sizes in 11 s-RI and 7 s-RI solutions characterized by D4,3. But salt addition reduced the viscosity in both protein solutions when their solid concentration rose to 16 % (11 s-RI) and 45 % (7 s-RI). It's concluded solventization and salting-out were the dominant effects of the decreasing viscosity in 11 s-RI and 7 s-RI phosphate solutions, respectively.

Effect of bacterial diversity on the quality of fermented apple juice during natural fermentation of Hanfu apples

The fermented cloudy apple juice (FCAJ) bacterial phase was analyzed by 16S rRNA gene-based sequencing. During fermentation, the bacterial phase transition promoted quality changes, such as carbohydrate, organic acid, total phenol, taste and volatiles of FCAJ. Citrobacter and Lactobacillus were the dominant bacterial genera of Hanfu apple juice by natural fermentation, and lactic acid was the most abundant organic acid in FCAJ. Citrobacter showed a continuous increase trend along with fermentation time, while Lactobacillus showed a slight decrease during the later period of fermentation. The contents of total phenolic and flavonoid both showed a trend of rising first and then decreasing in FCAJ during fermentation. Alcohols and esters, the main aromatic volatiles in FCAJ, showed significant increases, especially for ethanol, 3-methyl-1-butanol and ethyl acetate. Citrobacter presented a higher correlation than Lactobacillus with some volatile flavor.

Preparation, characterization and properties of chitosan-coated Epsilon-poly-lysine nanoliposomes in apple juice

Epsilon-poly-lysine (EPL) is widely used in food preservatives. However, EPL can react with components in food substrates, resulting in the formation of precipitates that reduce its antimicrobial properties. Nanoencapsulation is a promising technique and represents a novel approach to enhance EPL activity. In this study, EPL nanoliposomes (EPLLP) were prepared by the thin film hydration method, and chitosan-coated nanoliposomes (CS-EPLLP) were developed by modifying EPLLP with 0.5 mg/mL chitosan. The obtained CS-EPLLP exhibited a spherical morphology with a particle size range of 85.27-89.77 nm, a polydispersity index (PDI) of 0.293-0.301, and an encapsulation efficiency of 83.01 ± 4.00 %. After 30 days of storage, no significant difference in particle size was observed and the PDI was <0.30. The release rate of EPLLP was up to 40 % in 1 h, while that of CS-EPLLP was <20 %. The physical and thermal stability of EPLLP could be effectively improved by chitosan. Moreover, CS-EPLLP could effectively eradicate A. acidocaldarius and A. acidoterrestris in apple juice at concentrations of 2.5 and 0.625 mg/L, respectively. The cytotoxicity test showed that CS-EPLLP exhibited excellent biocompatibility. Therefore, this study has developed a novel nanoliposome material that provides new insights into the control of bacterial contamination in fruit juices.

Interaction between pea protein isolate and quercetin: Effects on protein conformation and quercetin activity

Comprehensive comprehension of the interaction between proteins and polyphenols is crucial for advancing their utilization in food processing. This study investigated no-covalent interaction between pea protein isolate (PPI) and quercetin (Que) through spectroscopic analysis and molecular simulation. Fourier transform infrared spectroscopy and circular dichroism spectrum showed that the interaction between PPI and Que changed the secondary structure of the protein due to a decrease in α-helix content and an increase in the random coil. Thermodynamic parameters indicated that the Quebound PPI via hydrogen bonds and hydrophobic interactions (ΔH > 0, ΔS > 0, and ΔG < 0), which was also confirmed by molecular docking. Particle size and ζ-potential showed that PPI and Que demonstrated effective interaction and binding capabilities, enhancing the stability. In addition, the antioxidant and bioaccessibility of complexes have also been enhanced. This study shed a light on the application of protein-polyphenol complexes for developing functional foods. PRACTICAL APPLICATION: Interaction between pea protein isolate and quercetin can change the protein conformation to maintain the stability of quercetin and is helpful to expand the market value and application value of plant protein. The research has important implications for using leguminous protein as embedded support to improve the stability of polyphenols compounds.

Stabilization of fermented tomato (Solanum lycopersicum L.) juice by differently charged hydrocolloids

This study investigated the impact of three different charged hydrocolloids, anionic polysaccharide (soluble soybean polysaccharide, SSPS), neutral polysaccharide (pullulan polysaccharide, PUL), and cationic polysaccharide (chitosan, CS), and their complexation on the stabilization efficiency of fermented tomato juice (FTJ). The effect of hydrocolloids on FTJ under different treatment conditions were comprehensively evaluated by determining the particle size distribution, zeta potential, rheological properties, Fourier transform infrared spectroscopy, surface tension, and LUMiSizer. The combined conditions suggest that PUL exhibits better storage stability than SSPS and CS when used individually. Compared with the use of the stabilizers, the combination of hydrocolloids had a greater impact on the storage stability of the FTJ, and the storage stability of the FTJ increased when 0.15% SSPS + 0.03% PUL + 0.15% CS was added. This study lays the groundwork for the development of stable fruit juice beverages.

Multifunctional metal-organic framework-enhanced sodium alginate-based intelligent indicator: Mechanism and application for freshness monitoring

Intelligent food packaging has recently gained significant attention due to the heightened consumer awareness regarding food quality. Although anthocyanins avoid safety issues, the instability and leakage of anthocyanins restrict their utilization in freshness indicator labels. In this study, we introduced an innovative metal-organic framework (UiO-66-NH2) synergistic pH-colorimetric label with fast ammonia-responsive, incorporating sodium alginate, red cabbage anthocyanin, and UiO-66-NH2. The cross-linked sodium alginate substrate enabled the label to possess superior insolubility. The microscopic morphology of the labels was intricately analyzed, while their sensitivity was rigorously tested utilizing ammonia as a representative gas. Due to the remarkable UV absorption capability of UiO-66-NH2 and various molecular interactions with anthocyanins, the label exhibited good UV absorption, enhanced stability, and optimized performance in reducing anthocyanin leakage, ensuring the stability and effectiveness of the labels in practical applications. The prepared label exhibited good specificity for volatile amines and ammonia gases, and robust anti-interference properties, enabling visualization and early detection of shrimp spoilage during storage at different temperatures. The strategy employed in this study presents promising new possibilities for developing intelligent packaging solutions for food products.

Ultra-high pressure treatment improve the content of characteristic aromatic components of melon juice from the view of physical changes

Introduction

The effectiveness of ultra-high pressure (UHP) technology in retaining the flavor of fresh fruit and vegetable juices has been acknowledged in recent years. Along with previously hypothesized conclusions, the improvement in melon juice flavor may be linked to the reduction of its surface tension through UHP.

Methods

In this paper, the particle size, free-water percentage, and related thermodynamic parameters of melon juice were evaluated in a physical point for a deeper insight.

Results

The results showed that the UHP treatment of P2-2 (200 MPa for 20 min) raised the free water percentage by 7,000 times than the other treatments and both the melting enthalpy, binding constant and Gibbs free energy of P2-2 were minimized. This significantly increased the volatility of characteristic aromatic compounds in melon juice, resulting in a 1.2-5 times increase in the content of aromatic compounds in the gas phase of the P2-2 group compared to fresh melon juice.

A fresh-cut papaya freshness prediction model based on partial least squares regression and support vector machine regression

This study investigated the physicochemical and flavor quality changes in fresh-cut papaya that was stored at 4 °C. Multivariate statistical analysis was used to evaluate the freshness of fresh-cut papaya. Aerobic plate counts were selected as a predictor of freshness of fresh-cut papaya, and a prediction model for freshness was established using partial least squares regression (PLSR), and support vector machine regression (SVMR) algorithms. Freshness of fresh-cut papaya could be well distinguished based on physicochemical and flavor quality analyses. The aerobic plate counts, as a predictor of freshness of fresh-cut papaya, significantly correlated with storage time. The SVMR model had a higher prediction accuracy than the PLSR model. Combining flavor quality with multivariate statistical analysis can be effectively used for evaluating the freshness of fresh-cut papaya.

Alteration of volatile profiles in heat-sterilized cloudy muskmelon juice as affected by pectin fractions

BACKGROUND

Flavor is considered as a key quality attribute of fruit juice affecting consumer acceptance. During processing, the flavor loss of cloudy juice always occurs due to the variations of juice cloud particles. Pectin, a major component of cloud particles, plays an important role in cloud stability. In this work, we focused on the effects of variation of three pectin fractions caused by gentle centrifugation and clarification on the physicochemical properties, volatile content and sensory profile of heat-sterilized muskmelon cloudy juice.

RESULTS

Centrifugation treatment reduced the total soluble solids and viscosity of cloudy juice and increased cloud stability. With centrifugation increased, the contents of most monosaccharides in the three pectin fractions were reduced. Most aroma-active aldehydes and alcohols, such as (2E,6Z)-nonadienal, 1-octen-3-ol and (E)-non-2-enal, after gentle centrifugation and clarification, were maintained, but most esters were decreased. The volatile compositions were highly related to the three pectin fractions. The addition of chelator-soluble pectin and sodium carbonate-soluble pectin could decrease the formation of dimethyl trisulfide and dimethyl disulfide in clarified juice, thereby improving the sensory profile.

CONCLUSION

The results suggested that endogenous chelator-soluble pectin and sodium carbonate-soluble pectin can be used in heat-sterilized fruit juice to improve flavor quality, with an emphasis on a significant reduction in volatile sulfur compounds. © 2023 Society of Chemical Industry.

Effect of Novel Processing Techniques on the Carotenoid Release during the Production of Red Guava Juice

Red guava, distinguished by its elevated lycopene content, emerges as a promising natural source of carotenoids. This study systematically evaluates the impact of diverse processing techniques on the efficient release of carotenoids. The primary objective is to facilitate the transfer of carotenoids into the juice fraction, yielding carotenoid-enriched juice seamlessly integrable into aqueous-based food matrices. The untreated guava puree exhibited a modest release of carotenoids, with only 66.26% of β-carotene and 57.08% of lycopene reaching the juice. Contrastly, both high-pressure homogenization (HPH) at 25 MPa and enzyme (EM) treatment significantly enhanced carotenoid release efficiency (p < 0.05), while high hydrostatic pressure (HHP) at 400 MPa and pulsed electric field (PEF) of 4 kV/cm did not (p > 0.05). Notably, HPH demonstrated the most substantial release effect, with β-carotene and lycopene reaching 90.78% and 73.85%, respectively. However, the stability of EM-treated samples was relatively poor, evident in a zeta-potential value of -6.51 mV observed in the juice. Correlation analysis highlighted the interactions between pectin and carotenoids likely a key factor influencing the stable dissolution or dispersion of carotenoids in the aqueous phase. The findings underscore HPH as a potent tool for obtaining carotenoid-enriched guava juice, positioning it as a desirable ingredient for clean-label foods.

A wide diversity exists in pectin structure from thirteen apple cultivars

To emphasize that differences in pectin structure among cultivars play a crucial role in the texture and quality of fruits and vegetables, the sugar content and methyl-esterification of pectin fractions from 13 apple cultivars was studied. Cell wall polysaccharides were isolated as alcohol-insoluble solids (AIS) and subsequently extracted to yield water-soluble solids (WSS) and chelating-soluble solids (ChSS). All fractions contained significant amounts of galacturonic acid, while sugar compositions varied between cultivars. AIS and WSS pectins showed a degree of methyl-esterification (DM) > 50 %, while ChSS pectins had either a medium (~50 %) or low (<30 %) DM. Homogalacturonan as major structure was studied using enzymatic fingerprinting. Methyl-ester distribution of pectin was described by degrees of blockiness and -hydrolysis. Novel descriptive parameters were obtained by measuring the levels of methyl-esterified oligomers released by endo-PG (DB_PGme) and PL (DB_PLme). Pectin fractions differed in relative amounts of non-, moderately-, and highly methyl-esterified segments. WSS pectins were mostly lacking non-esterified GalA sequences, while ChSS pectins had medium DM and many non-methyl-esterified blocks or a low DM with many intermediate methyl-esterified GalA blocks. These findings will be of help to better understand physicochemical properties of apple and its products.

Effect of Surfactant Formula on the Film Forming Capacity, Wettability, and Preservation Properties of Electrically Sprayed Sodium Alginate Coats

Surfactants are always added to coating formulations to ensure good adhesion of edible coatings to a product's surface and to maintain freshness. In this study, the effects of the mix surfactants Tween 20 and Span 80 with different hydrophile-lipophile balance (HLB) values on the film-forming ability, wettability, and preservation capacity of blueberry sodium alginate coating were investigated. The results indicated that Tween 20 obviously ensured favorable wettability and improved the uniformity and mechanical properties of the resulting film. While the addition of Span 80 reduced the mean particle size of the coating, enhanced the water resistance of the film, and helped to reduce blueberry weight loss. A sodium alginate coating with low viscosity and medium HLB could better inhibit the galactose, sucrose, and linoleic acid metabolism of blueberries, reduce the consumption of phenols, promote the accumulation of flavonoids, and thus display superior coating performance. In summary, sodium alginate coating with medium HLB had comprehensive advantages in film-forming ability and wettability and was conducive to the fresh-keeping role.

Characterization of the flavor, sensory quality and in vitro bioaccessibility in cloudy pomegranate juice treated by high pressure and thermal processing

BACKGROUND

Recently, cloudy pomegranate juice (PJ) has become popular due to its rich phenolic and health-promoting effects. The aim of the present work was to evaluate the application of high hydrostatic pressure processing (HPP), pasteurization (PT) and high-temperature short-time sterilization (HTST) on physicochemical properties (color, flow behavior, turbidity, sugars, organic acids, aroma and sensory evaluation) and in vitro bioaccessibility of total phenolics content (TPC), total flavonoids content (TFC) and phenolics of cloudy PJ.

RESULTS

Compared to HPP, thermal sterilization significantly increased the brightness (L*), redness (a*), total color difference (ΔE) and turbidity, and decreased the TPC and TFC. HPP maintained the volatile profile of cloudy PJ better, while thermal sterilization significantly changed the profile by decreasing alcohols 23.8-32.7% and increasing acids by 33.6%-182.8%. The bioaccessibility of flavonoids, phenolic acids and tannins in the control cloudy PJ after in vitro oral-gastric-intestinal digestion were 1.5%, 4.9%, and 9.0%, respectively, which were not significantly changed by different treatments.

CONCLUSION

These results contributed to promoting the color quality and health benefits of cloudy PJ rich in phenolics by optimizing the processing conditions in the food industry. © 2022 Society of Chemical Industry.

A Novel Strategy to Improve Cloud Stability of Orange-Based Juice: Combination of Natural Pectin Methylesterase Inhibitor and High-Pressure Processing

This study investigated the prospect of producing cloud-stable orange-based juice by combining high-pressure processing (HPP) with a natural kiwifruit pectin methylesterase inhibitor (PMEI) during chilled storage. Kiwifruit is rich in a PMEI, which greatly improves the cloud loss caused by the pectin methylesterase (PME) demethylation of pectin. The results show that the cloud loss of orange juice occurred after 3 days, while the orange-kiwifruit mixed juice and kiwifruit puree were cloud stable during 28 days' storage. Although, the kiwifruit puree contained larger particles compared to the orange juice, its higher viscosity and solid-like behavior were dominant, improving the cloud stability of the juice systems. In addition, the particle size distribution and rheological properties were highly related to PME activity, PMEI activity, and pectin characterization. The kiwifruit PMEI showed higher resistance to HPP and storage time than PME. More water-solubilized pectin fractions with a high molecular mass were found in the kiwifruit puree, leading to its high viscosity and large particle size, but a more chelator-solubilized pectin fraction with a low esterification degree was observed in the orange juice, resulting in its cloud loss. In general, the outcome of this work provides a novel strategy to improve the cloud stability of orange-based juices using natural PMEIs and nonthermal processing technologies.

Delivery of Catechins from Green Tea Waste in Single- and Double-Layer Liposomes via Their Incorporation into a Functional Green Kiwifruit Juice

Globally, about one million tonnes of tea products, which contain high concentrations of catechins and their derivatives, are wasted annually. Therefore, green tea waste catechins (GTWCs) are worth extracting, processing, protection, and delivery to the human body. In this study, GTWCs were extracted using a green method and then encapsulated in both single- (SLLs) and double-layer liposomes (DLLs). The encapsulated extracts were subsequently incorporated into a fresh green kiwifruit juice. SLLs and DLLs containing GTWCs had a size of about 180 and 430 nm with a zeta potential of -35 and +25 mV, respectively. Electron microscopy illustrated the separation of the SLLs and fibre in kiwifruit juice and attraction of the DLLs to this fibre. Liposomal GTWCs were effectively maintained in the kiwifruit juice during the 28 days of storage (4 °C), demonstrating the effectiveness of this delivery system for high-value bioactives (i.e., catechins) from such a by-product (i.e., green tea waste).

Effect of combined ultrasonic and enzymatic extraction technique on the quality of noni (Morinda citrifolia L.) juice

In order to obtain noni juice with high yield and good quality, the effect of combined extraction technique of enzymatic treatment (EZ) and ultrasonication (US) on the overall quality of noni juice was investigated. Moreover, the extraction performance of the EZ-US combined extraction technique was compared with that of EZ-based extraction and the US-based extraction. Response surface methodology (RSM) was designed to optimize the parameters of ultrasonic treatment, by taking consideration of the extraction efficiency, quality parameters and bioactive ingredients of noni juice. The results indicated that combined ultrasonic and enzymatic treatment achieved a synergistic effect on promoting the quality of noni juice. The maximum juice yield of 67.95 % was obtained under ultrasonication for 10 min at 600 W after enzymatic treatment (EZU). In addition, EZU-treated juice exhibited the highest contents of total phenolic and flavonoid, which were 148.19 ± 2.53 mg gallic acid/100 mL and 47.19 ± 1.22 mg rutin/100 mL, respectively, thus contributing to better antioxidant activity. Moreover, the EZU treatment significantly reduced the particle size of noni juice, and improved its suspension stability and rheological properties. FTIR results indicated that the treatments did not bring major changes in the chemical structure and the functional groups of compounds in noni juice. Therefore, EZU treatment can be successfully applied to the extraction of noni juice with better nutritional properties and overall quality.

Cloud stabilization of citrus fruit juices treated with purified pectin methylesterase inhibitor from lemon (Citrus limon L.)

BACKGROUND

Cloud destabilization is a significant quality defect of cloudy fruit juices. A proteinaceous inhibitor (PMEI) of pectin methylesterase (PME), identified in lemon, with a fold purity of 89.13, was used to stabilize the cloud of freshly prepared sweet lime, orange, and lemon juice.

RESULTS

Lemon PMEI was able to inhibit the PME activity of all three fruit juices. In this study addition of calculated amounts of lemon PMEI to the three juice systems was based on the total PME units present in each juice. Relative turbidity, viscosity, pH, and ζ -potential of the PMEI-treated juices were stable, resulting in uniform distribution of cloud particles throughout the juice system. The sedimentation rate in PMEI treated juices was very low, with cloud particles having smaller particle size diameter.

CONCLUSION

This work demonstrates an alternative option that might create new potential to control the quality deterioration in cloudy fruit juices. © 2022 Society of Chemical Industry.

Effects of Fruit Storage Temperature and Time on Cloud Stability of Not from Concentrated Apple Juice

Apple juice that is designated ‘Not from concentrated’ (NFC) is now increasingly popular with consumers due to its unique taste and rich nutritional value. However, layered precipitation and instability have emerged as serious technical problems that restrict the viability of the NFC apple juice industry. This study researched the influence of water-cored ‘Fuji’ apple fruit storage under different temperatures (0, 20 °C) and times (0, 9, 18, 30, 60 days) on the turbidity stability of NFC apple juice. Changes in the physicochemical properties (juice yield, pH, total soluble solids and titratable acid), turbidity stability (turbidity and particle size) and precipitation sensitive substances (insoluble starch, total phenolics, soluble protein and pectin) of NFC apple juice were determined, combined with the respiratory rates and ethylene release of apples, in order to study post-harvest regulation and control of processed fruit. Results indicated that fruit storage temperature and time significantly guided the turbidity stability of NFC apple juice. As a typical respiratory climacteric fruit, apple fruit stored 45 days at 0 °C and 15 days at 20 °C gained the best juice stability, respectively. This is basically consistent with the respiratory peak of fruit when processing raw materials. During the post-ripening process, the insoluble starch in apple gradually hydrolyzed into fructose and glucose, while total phenolics diminished and water-soluble pectin content increased. On the other hand, the amounts of pectin, soluble protein and phenolics in fruit juice declined as the fruit aged in the late storage period (stored 75 days at 0 °C and 40 days at 20 °C). Meanwhile particle size became larger and the turbidity stability of cloudy juices also decreased. This study’s results will provide a sound theoretical basis for improving the turbidity stability of NFC apple juice by regulating the physiological state of processed raw materials.

Athermal Concentration of Blueberry Juice by Forward Osmosis: Food Additives as Draw Solution

This study is to evaluate the athermal forward osmosis (FO) concentration process of blueberry juice using food additives as a draw solution (DS). The effects of food additives, including citric acid, sodium benzoate, and potassium sorbate, on the concentration processes are studied, and their effects on the products and membranes are compared. Results show that all these three food additives can be alternative DSs in concentration, among which citric acid shows the best performance. The total anthocyanin content (TAC) of blueberry juice concentrated by citric acid, sodium benzoate, and potassium sorbate were 752.56 ± 29.04, 716.10 ± 30.80, and 735.31 ± 24.92 mg·L^-1, respectively, increased by 25.5%, 17.8%, and 19.9%. Meanwhile, the total phenolic content (TPC) increased by 21.0%, 10.6%, and 16.6%, respectively. Citric acid, sodium benzoate, and potassium sorbate all might reverse into the concentrated juice in amounts of 3.083 ± 0.477, 1.497 ± 0.008, and 0.869 ± 0.003 g/kg, respectively. These reversed food additives can make the TPC and TAC in juice steadier during its concentration and storage. Accordingly, food additives can be an excellent choice for DSs in the FO concentration process of juices, not only improving the concentration efficiency but also increasing the stability of blueberry juice.

Improving the quality of mandarin juice using a combination of filtration and standard homogenization

Cloud loss and pulp precipitation are serious quality defects of mandarin juice (MJ) which brake on industrialization and need to be overcome by developing stabilization process. Therefore, filtration (FT) and standard homogenization (SH) on improving the cloud stability of MJ and minimizing the loss of major qualities were investigated. The FT-SH combined treatment effectively decreased the minimal particle size below 15 μm and sedimentation rate by 17.30%-74.40%, and increased the cloud value from 7.97% to 332.57%, results in more uniformity and cloud stability of MJ. Moreover, FT reduced the pectin methylesterase (PME) activity by 34.19%-50.96%, browning (ΔE^∗ < 3), free and bound phenol contents (27.81% and 59.13%), and aroma intensity (p < 0.05). SH released the free phenols from bound phenols association with cloudiness. The optimum stabilization condition was considered as the 100-mesh + 20 MPa that was obviously improved the cloudiness and minimizing the color, polyphenol and aroma loss.

Role of pectin characteristics in orange juice stabilization: Effect of high-pressure processing in combination with centrifugation pretreatments

"High-pressure processing (HPP) plus" combined technologies are applied to overcome the limitation of single HPP and to produce juices with more stable quality during storage. This research explored the potential of HPP in combination with centrifugation to produce cloud stable orange juice during refrigerated storage. The results indicated that HPP combined processing technology significantly improved the cloud stability of orange juice, which was related to removed large particles, reduced viscosity, decreased protein contents, and inactivated pectin methylesterase activity induced by centrifugation (P < 0.05). Besides, chelator solubilized pectin (CSP) decreased but water solubilized pectin (WSP) maintained in the juice after centrifugation. During storage, the conversion of pectin fraction from WSP to CSP, resulting in sedimentation appeared in centrifugation treated orange juice when stored for 28 days. In general, pectin characteristics changes and pectin fractions conversion were the main driving forces affecting cloud stability of orange juice pasteurized by HPP in combination with centrifugation and during chilled storage.

Quality changes and shelf-life prediction model of postharvest apples using partial least squares and artificial neural network analysis

The quality of postharvest apples is greatly affected by storage temperatures. In this paper, the sensory qualities, such as flavor, texture, color, and taste change of apples during storage at 4 °C and 20 °C were investigated. After correlation analysis, the partial least squares (PLS) and artificial neural network (ANN) techniques were used to build a shelf-life prediction model. The results showed that lower temperature storage can better maintain the color, flesh hardness, and release of volatile compounds of apples. The acidity of apples stored at 20 °C decreased much faster than that at 4 °C. The PLS models were successful in predicting the apple shelf life. When modeling using PLS with a single type index, the order of accuracy of the prediction model was texture, color, and flavor. As a nonlinear algorithm, the ANN model was also an effective predictive tool of apple shelf life at both temperatures.

Ultrasonic and other sterilization methods on nutrition and flavor of cloudy apple juice

Sterilization plays an important role in extending the shelf-life of apple juice; however, it also affects the nutritional and flavor profile of the juice. This study was initiated to evaluate the effects of several common sterilization methods (conventional pasteurization, microwave sterilization, ultrasonic sterilization, and ultra-high-pressure sterilization) on some important quality parameters of apple juice. The results showed that the content of soluble pectin and soluble protein in juice decreased significantly after ultra-high-pressure sterilization. Sonication was found to be effective in increasing the level of ascorbic acid in apple juice. The sugar:acid ratio increased significantly after pasteurization, microwave sterilization, and ultra-high-pressure sterilization, which changed the taste of juice. Microwave sterilization caused the highest volatile compound loss, while ultra-high-pressure sterilization led to a higher retention rate of volatile compounds in juice. This study could be helpful in seeking suitable sterilization methods retaining the quality of cloudy apple juice.

Effect of Galangal Essential Oil Emulsion on Quality Attributes of Cloudy Pineapple Juice

Galangal essential oil is obtained from the rhizomes of galangal with proven anti-inflammatory, antioxidant, antiviral, and antimicrobial properties, which are valuable in the food industry. To explore the effect of galangal essential oil on the quality of pineapple juice, 0.05, 0.1, 0.2, and 0.4% galangal essential emulsion were added, and their influence on the physical stability, physicochemical properties, microbial quantity, and aroma profiles of cloudy pineapple juice were evaluated. The essential oil emulsion of galangal is a milky white liquid with a strong aroma of galangal. The pH values of emulsion increased from 4.35 to 5.05 with the increase in essential oil concentration, and there was no significant difference in the particle size of the pineapple juice. The results showed that the galangal essential oil emulsion was stable and the stability of the cloudy pineapple juice was significantly enhanced by the essential oil emulsion determined using LUMiSizer. The cloudy pineapple juice with a 0.2% essential oil emulsion showed the most stability during storage. The lightness of the cloudy pineapple juice increased instantly with the essential oil emulsion addition. In addition, the microbial quantity of the cloudy pineapple juice was decreased by the individual essential oil emulsion or combined with thermal treatment to hold a longer shelf life. The microbial counts in pineapple juice treated by 0.4% essential oil emulsion and thermal treatment only increased from 1.06 to 1.59 log CFU/ml after 4 days of storage at 25°C. Additionally, the pH and total soluble solids showed a slightly increasing trend; however, the value of titratable acidity, free radical scavenging capacity, and ascorbic acid content of the cloudy pineapple juice showed no significant change. Finally, the results of the electronic nose showed that the aroma components of the pineapple juice were changed by the essential oil emulsion and thermal treatment, and the difference was especially evident in the content of the sulfur, sulfur organic, and aromatics compounds. Consequently, the results indicated that galangal essential oil emulsion can be used as juice additives to improve the quality attributes and extend the shelf-life of cloudy pineapple juice.

Effect of centrifugal pre-treatment on flavor change of cloudy orange juice: Interaction between pectin and aroma release

Cloud loss of orange juice could be effectively inhibited by centrifugal treatment, but it can induce flavor changes, which become a new challenge for the industry. This work aims to investigate the effect of centrifugation on flavor changes in orange juice and explore its possible mechanism. Taste- and aroma-related attributes were analyzed, and pectin was characterized. Results indicated that pH (4.00), total soluble solid (9.67 °Brix), titratable acidity (0.42%), sucrose (44%), fructose (29%), and glucose (27%) were less affected by centrifugation (P > 0.05). However, aroma compounds significantly changed (P < 0.05), where terpenes and alcohols tended to be distributed in pulp and serum after centrifugation, respectively. Pearson correlation analysis showed that aroma compound distribution induced by centrifugation was highly related to chelator-solubilized pectin fraction and sodium carbonate-solubilized pectin fraction (|R| > 0.9). In general, centrifugation clearly changed aroma of orange juice, which was mainly affected by pectin characteristics.

Impact of high-intensity thermosonication treatment on spinach juice: Bioactive compounds, rheological, microbial, and enzymatic activities

To study the impacts of thermosonication (TS), the spinach juice treated with TS (200 W, 400 W, and 600 W, 30 kHz, at 60 ± 1 °C for 20 mint) were investigated for bioactive compounds, antioxidant activities, color properties, particle size, rheological behavior, suspension stability, enzymatic and microbial loads. As a result, TS processing significantly improved the bioactive compounds (total flavonols, total flavonoids, total phenolic, carotenoids, chlorophyll, and anthocyanins), antioxidant activities (DPPH and FRAP assay) in spinach juice. Also, TS treatments had higher b*,L*, hue angle (h0), and chroma (C) values, while minimuma* value as compared to untreated and pasteurized samples. TS processing significantly reduced the particle size, improved the suspension stability and rheological properties (shear stress, apparent viscosity, and shear rate) of spinach juice as compared to the untreated and pasteurized sample. TS plays a synergistic part in microbial reduction and gained maximum microbial safety. Moreover, TS treatments inactivated the polyphenol oxidase and peroxidase from 0.97 and 0.034 Abs min-1 (untreated) to 0.31 and 0.018 Abs min-1, respectively. The spinach juice sample treated at a high intensity (600 W, 30 kHz, at 60 ± 1 °C for 20 mint, TS3) exhibited complete inactivation of microbial loads (<1 log CFU/ml), the highest reduction in enzymatic activities, better suspension stability, color properties, and highest bioactive compounds. Collectively, the verdicts proposed that TS processing could be a worthwhile option to pasteurize the spinach juice to enhance the overall quality.

Ultrasonication of Thawed Huyou Juice: Effects on Cloud Stability, Physicochemical Properties and Bioactive Compounds

In order to remove the flocculent precipitation in Huyou juice after frozen storage and thawing process, the thawed juice was ultrasonically treated with different power (45-360 W) and time (10-60 min) in ice bath (~0 °C), and its sedimentation behavior during storage was observed. After optimization, the cloud stability of juice could be improved by ultrasonic treatment with ultrasonic power of 360 W or more for at least 30 min, which could be stable during 7 days of storage at 4 °C. Under this optimal condition (360 W, 30 min), the effects of ultrasound on the physicochemical properties and bioactive compounds of thawed Huyou juice during storage were investigated. The results showed that with smaller particle size and lower polymer dispersity index, ultrasonic treatment did not significantly change the color, soluble solids, titratable acidity, and bioactive compounds including flavonoids and other phenolics. In addition, all properties of samples were at the same level during storage. Thus, ultrasound was applicable since it can improve the cloud stability of Huyou juice with minimal impact on its physicochemical properties and nutritional quality compared to the untreated one.

Optimization of the extraction conditions and dermal toxicity of oil body fused with acidic fibroblast growth factor (OLAF)

INTRODUCTION

Oil body (OB), a subcellular organelle that stores oil in plant seeds, is considered a new transdermal drug delivery system. With the increasing understanding of the OB and its main protein (oleosin), numerous studies have been conducted on OB as "carrier" for the expression of exogenous proteins. In our previous study, oil body fused with aFGF (OLAF) was obtained using a plant oil body expression system that had been preliminarily proven to be effective in accelerating the healing of skin wounds. However, no dermal toxicological information on OLAF is available.

OBJECTIVE

To ensure the dermal safety of OLAF, a series of tests (the acute dermal toxicity test, 21-day repeat dermal toxicity test, dermal irritation test and skin sensitisation test) were conducted after optimising the extraction protocol of OLAF.

MATERIALS AND METHODS

To improve the extraction rate of OLAF, response surface methodology (RSM) was first employed to optimise the extraction conditions. Then, Wistar rats were exposed to OLAF (400 mg·kg^-1 body weight) in two different ways (6 hours/time for 24 hours and 1 time/day for 21 days) to evaluate the acute dermal toxicity and 21-day repeated dermal toxicity of OLAF. In the acute dermal toxicity test, clinical observations were conducted to evaluate the toxicity, behaviour, and health of the animals for 14 consecutive days. Similarly, the clinical signs, body weight, haematological and biochemical parameters, histopathological changes and other indicators were also detected during the 21 days administration. For the dermal irritation test, single and multiple doses of OLAF (125 mg·kg^-1 body weight) were administered to albino rabbits for 14 days (1 time/day). The irritation reaction on the skin of each albino rabbit was recorded and scored. Meanwhile, skin sensitisation to OLAF was conducted using guinea pigs for a period of 28 days.

RESULTS

Suitable extraction conditions for OLAF (PBS concentration 0.01, pH of PBS 8.6, solid-liquid ratio 1:385 g·mL^-1) were obtained using RSM. Under these conditions, the extraction rate and particle size of OLAF were 7.29% and 1290 nm, respectively. In the tests of acute dermal toxicity and 21-day repeated dermal toxicity, no mortality or significant differences were observed in terms of clinical signs, body weight, haematological parameters, biochemical parameters and anatomopathological analysis. With respect to the dermal irritation test and skin sensitisation test, no differences in erythema, oedema or other abnormalities were observed between treatment and control groups on gross and histopathological examinations.

CONCLUSIONS

The results of this study suggest that OLAF does not cause obvious toxicity, skin sensitisation or irritation in animals.

Effect of Ginger on Chemical Composition, Physical and Sensory Characteristics of Chicken Soup

In order to investigate the effect of ginger on taste components and sensory characteristics in chicken soup, the content of amino acids, organic acids, 5′-nucleotides, and mineral elements were determined in chicken soup sample. With the ginger added, free amino acids in chicken soup obviously increased and exceeded the total amounts in ginger soup and chicken soup. The content of glutamic acid (122.74 μg/mL) was the highest among 17 free amino acids in ginger chicken soup. Meanwhile, six organic acids detected in chicken soup all obviously increased, among which lactic acid (1523.58 μg/mL) and critic acid (4692.41 μg/mL) exceeded 1000 μg/mL. The content of 5′-nucleotides had no obvious difference between ginger chicken soup and chicken soup. Compared with chicken soup, ginger chicken soup had a smaller particle size (136.43 nm) and color difference (79.69), but a higher viscosity. With ginger added in chicken soup, the content of seven mineral elements was reduced, and the content of total sugar increased. Results from an electronic tongue indicated a difference in taste profiles among the soups. The taste components and sensory quality of chicken soup were obviously affected by adding the ginger.

NMR Characterization of Ten Apple Cultivars from the Piedmont Region

The metabolite profile of ten traditional apple cultivars grown in the Piedmont region (Italy) was studied by means of nuclear magnetic resonance spectroscopy, identifying an overall number of 36 compounds. A more complete assignment of the proton nuclear magnetic resonance (¹H NMR) resonances from hydroalcoholic and organic apple extracts with respect to literature data was reported, identifying fructose tautomeric forms, galacturonic acid, γ-aminobutyric acid (GABA), p-coumaroyl moiety, phosphatidylcholine, and digalactosyldiacylglycerol. The chemical profile of each apple cultivar was defined by thorough quantitative NMR analysis of four sugars (fructose, glucose, sucrose, and xylose), nine organic acids (acetic, citric, formic, citramalic, lactic, malic, quinic, and galacturonic acids), six amino acids (alanine, asparagine, aspartate, GABA, isoleucine, and valine), rhamnitol, p-coumaroyl derivative, phloretin/phloridzin and choline, as well as β-sitosterol, fatty acid chains, phosphatidylcholine, and digalactosyldiacylglycerol. Finally, the application of PCA analysis allowed us to highlight possible differences/similarities. The Magnana cultivar showed the highest content of sugars, GABA, valine, isoleucine, and alanine. The Runsé cultivar was characterized by high amounts of organic acids, whereas the Gamba Fina cultivar showed a high content of chlorogenic acid. A significant amount of quinic acid was detected in the Carla cultivar. The knowledge of apple chemical profiles can be useful for industries interested in specific compounds for obtaining ingredients of food supplements and functional foods and for promoting apple valorization and preservation.