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Corrigendum to “Quality change during high pressure processing and thermal processing of cloudy apple juice” [LWT - Food Sci. Tech. 75 January 2017, 85–92]
... In canned tomato pulp products,Porretta et al. (1995) noticed the levels of alcohols decreased after treatment at ultrahigh temperature. In other investigations, HHP treatment markedly modified the volatile odor compounds of several juices(Santhirasegaram, Razali, George, & Somasundram, 2015;Yi et al., 2017;Zheng et al., 2016). In this study, pressure had the greatest effects on the type and contentof aldehydes. ...
The changes and relationships between the volatile compounds and fatty acids, and between volatile compounds and free amino acids were analyzed after they were handled by 400 and 500 MPa (45°C/10 min) high hydrostatic pressure (HHP). The volatile components of 31, 30, and 32 were detected in the untreated, 400, and 500 MPa samples, respectively. Unlike the ketones and acids, the three contents, including ester (59.59%–71.34%), alcohol (5.95%–7.56%), and aldehyde (0.36%–1.25%), were greatly changed. While HHP treatment exerted a few effects on the contents of 12 kinds of fatty acids. With the increase in pressure, the contents of palmitic acid, linolenic acid, and α‐linolenic acid were remarkably reduced. The correlations between flavor compounds and amino acids, and between flavor compounds and fatty acids were studied by Pearson's correlation analysis and visualized with using the corrplot package in R software. The analysis showed that the amino acids were positively correlated with (E)‐6‐nonenal, (2E,6Z)‐nona‐2,6‐dienal and (Z)‐6‐nonen‐1‐ol, while they were negatively correlated with nonanal, (Z)‐3‐hexen‐1‐ol and ethyl caproate. Besides, the fatty acids were positively correlated with the esters of 2,3‐butanediol diacetate and 2‐methyl propyl acetate, while they were negatively correlated with (E)‐2‐octenal and (Z)‐6‐nonen‐1‐ol. The changes and relationships between the volatile compounds, fatty acids, and free amino acids of Hami melon juice, treated by high hydrostatic pressure.
For the first time, the efficacy of low intensity (1–7 V/cm) direct-current (DC) electric field in preventing browning in apple juice is examined. The results show that applying a 5 V/cm electric field can inactivate 89.24% of polyphenol oxidase (PPO) within 90 min and achieve complete inactivation of peroxidase (POD) within 70 min, maintaining the juice temperature below 30 ◦C throughout the process. The Weibull model fits the PPO and POD inactivation effectively, suggesting varied responses among isoenzymes. Under the optimal conditions (5 V/cm for 90 min), a 15.89% increase in total phenolic content (TPC) was observed alongside
significant improvements in antioxidant activity. Furthermore, this method preserved the natural flavor and lightened the color of the apple juice, enhancing its sensory appeal. These findings indicate that low intensity DC electric field is an innovative and effective choice for preventing juice browning, offering significant potential for application in the food industry.
This study investigated the effect of dense phase carbon dioxide (DPCD) treatment on the organoleptic properties of new-paocai. Optimal DPCD treatment (25 MPa/40 °C/40 min) was determined by conducting single-factor and orthogonal experiments with the sensory, bactericidal, and electronic eye evaluations. DPCD treatment (25 MPa/40 °C/40 min) did not significantly affect the nitrite, pH, total acid, and organic acid of the new-paocai brine, and the texture of the radish slices did not display substantial changes. Gas chromatography-mass spectrometry (GC–MS) was employed to characterize the new-paocai brine flavor, revealing 63 and 60 respective flavor compounds with and without DPCD treatment. In addition, DPCD treatment significantly reduced the total organic volatile compound content in the paocai from 48.182 μg/mL to 35.952 μg/mL, DPCD has a great influence on volatile flavor substances. The electronic nose (E-nose) effectively distinguished the flavor differences in the new-paocai brine with and without DPCD treatment. This study combined new food processing technology with traditional food production, could provide a new idea for pickle production technology.
The influences of ultra-high pressure (UHP), ultrasound (US) and their combination (UHP-US) assisted vacuum-freeze drying on volatile and taste compounds of strawberry slices were analyzed by GC-MS, HS-GC-IMS, HPLC, E-tongue as well as sensory analysis. Three pretreatments of vacuum-freeze dried strawberry slices could increase the concentrations of characteristic volatile compounds (hexanoates and 2,5-dimethyl-4-methoxy-3(2H)-furanone), especially UHP-US (P < 0.05) sample, the increase of compounds associated with floral, fruity and sweet notes. Meanwhile, these pretreatments would ameliorate the taste of dried strawberry slices, individual sugars (glucose and fructose) increased, while the organic acids (malic acid and citric acid) contents decreased, which was consistent with the result of E-tongue. On the other hand, the taste of US sample was better than other samples, the glucose and fructose content (sweetness) of US sample increased by 19.42%, 23.51%, respectively, whereas the malic acid content (sourness) was decreased for 5.03%. All in all, US pretreatment would help to better improve the critical flavors for vacuum-freeze dried strawberry slices.
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BACKGROUND
Flavor loss is a common problem when manufacturing apple juice and is closely related to the properties of the colloidal pectin particles in cloudy juice. The flavor changes and particle properties of three varieties of apple juice (‘Ralls’, ‘Golden Delicious’ and ‘Fuji’) during processing were investigated.
RESULTS
Compared with manually pressed juice, juice made by industrial pulping and filtration contained larger particles, resulting in the ‘sweet and sour’ taste of the juice being relatively weak and the diversity of aromas narrower, as determined by E‐nose analysis. Pulping and filtration, however, released some important flavor esters, such as butyl butyrate, hexyl‐2‐methyl butyrate, and hexyl butyrate. The transformation of volatile compounds during apple juice processing was closely related to the apple cultivar but, in all three varieties, the content of 1‐hexanal and (E)‐2‐hexenal in the juice gradually decreased during processing. Pectinase treatment reduced the colloid particle size and increased the ζ‐potential of the juice, resulting in better uniformity and stability, as well as increasing the content of nonanal. After pasteurization, the colloidal particles tended to aggregate and the ζ‐potential decreased. Many volatile compounds decreased in concentration or disappeared after heat treatment.
CONCLUSION
The flavor and colloidal properties of cloudy apple juice changed markedly during processing and the effect of each processing step was different. © 2020 Society of Chemical Industry
Acidity is an important influence factor for juice stability. In this study, the effects of acidityon stability of cloudy apple juice were investigated. The stability indexes, such as, turbidity, cloudvalue, cloud stability, and particle size distribution (PSD) were measured at pH 2.0, 2.5, 3.0 and 3.5,along with the untreated juice (pH 3.8) as control group. The results showed that, pH has significanteffects on turbidity, chrome (C*), cloud value, and D50, D90 in PSD of cloudy apple juice. The juicehad a better stabilization at pH 2.5. At this pH condition, the turbidity, cloud value, cloud stability ofjuice was the best. In addition, at pH 2.5, the color of the juice was better, the particles were smaller,and the particle sizes were more uniform. By this study, a theoretical reference could be provided forimproving stability of cloudy apple juice and extending juice shelf life.
The activity of endogenous deteriorative enzymes together with microbial growth (with associated enzymatic activity) and/or other non-enzymatic (usually oxidative) reactions considerably shorten the shelf life of fruits and vegetable products. Thermal processing is commonly used by the food industry for enzyme and microbial inactivation and is generally effective in this regard. However, thermal processing may cause undesirable changes in product's sensory as well as nutritional attributes. Over the last 20 years, there has been a great deal of interest shown by both the food industry and academia in exploring alternative food processing technologies that use minimal heat and/or preservatives. One of the technologies that have been investigated in this context is high-pressure processing (HPP). This review deals with HPP focusing on its effectiveness for controlling quality-degrading enzymes in horticultural products. The scientific literature on the effects of HPP on plant enzymes, mechanism of action, and intrinsic and extrinsic factors that influence the effectiveness of HPP for controlling plant enzymes is critically reviewed. HPP inactivates vegetative microbial cells at ambient temperature conditions, resulting in a very high retention of the nutritional and sensory characteristics of the fresh product. Enzymes such as polyphenol oxidase (PPO), peroxidase (POD), and pectin methylesterase (PME) are highly resistant to HPP and are at most partially inactivated under commercially feasible conditions, although their sensitivity towards pressure depends on their origin as well as their environment. Polygalacturonase (PG) and lipoxygenase (LOX) on the other hand are relatively more pressure sensitive and can be substantially inactivated by HPP at commercially feasible conditions. The retention and activation of enzymes such as PME by HPP can be beneficially used for improving the texture and other quality attributes of processed horticultural products as well as for creating novel structures that are not feasible with thermal processing.
‘Pink Lady’ is a late maturing ‘Lady Williams’ × ‘Golden Delicious’ apple (Malus domestica Borkh.) cultivar developed in Western Australia and imported into New Zealand by the Ministry of Agriculture and Fisheries in 1986. We used trained and consumer panellists, and chemical and physical analyses, to compare the sensory quality of ‘Pink Lady’ with that of four standard late‐harvest apple cultivars. If acceptable, the new apple could usefully extend the harvest season of New Zealand apples. Trained taste panellists gave ‘Pink Lady’ apples similar ratings to ‘Braeburn’ and ‘Fuji’ apples for texture, sweet‐sour balance and flavour, but lower ratings for juiciness. ‘Pink Lady’ was a firm apple as measured by penetrometer, and Instron texture measurements indicated it was a hard, crisp apple. ‘Pink Lady’, ‘Braeburn’, and ‘Fuji’ apples were rated higher for acceptability than ‘Granny Smith’ and ‘Red Dougherty’ by the consumer panel, who said they would buy these cultivars and pay more for them. Consumers also preferred the appearance of ‘Pink Lady’ apples. Changes in sensory quality during storage (as measured by sweetness, flavour, crispness, and juiciness) were similar for ‘Pink Lady’ and the four late‐maturing commercial cultivars tested. ‘Pink Lady’ had a musty off‐flavour initially that disappeared during storage, whereas other cultivars developed metallic, “old”, and alcoholic flavours. ‘Pink Lady’ apples browned quite slowly when sliced. Compositional analysis snowed ‘Pink Lady’ was relatively high in dry matter, soluble solids, and titratable acids.
The effects of supercritical carbon dioxide (SCCO2) treatment of 8, 15, 22, and 30MPa for 60min at 55C on polyphenol oxidase (PPO) activity, color, and browning degree in cloudy apple juice during storage at 4C for 4-weeks were investigated. The SCCO2 treatment had significant effects on inactivation of PPO and the least residual activity of PPO was 38.50% at 30MPa. The restoration of PPO residual activity after SCCO2 treatment was also observed, which was dependent on the pressure level. A greater reduction of lightness L and a minor increase of redness a of cloudy apple juices after SCCO2 treatment occurred. Moreover, the total color difference (ΔE), which was significantly less than that of untreated sample, was decreased by enhancing the pressure level. The changes of lightness L and browning degree A during storage were well fitted to a first-order kinetic model. The rate constants of k
L
and k
A
of samples subjected to SCCO2 treatment reduced from 4.7510−2 to 0.4210−2 and 37.1910−2 to 8.0210−2, respectively, when pressure increased from 0MPa (untreated sample) to 30MPa.
The purpose of this study was to investigate the effect of high hydrostatic pressure with a mild heat treatment on Staphylococcus aureus 485, Escherichia coli O157:H7 933 and Salmonella Enteritidis FDA in apple, orange, apricot and sour cherry juices. The effectiveness of the treatment on polyphenol oxidase activity in apple juice and pectinesterase activity in orange juice were also determined. An inoculum of microorganisms was completely inactivated at 350 MPa and 40 °C in 5 min. The residual polyphenol oxidase activity in apple juice after treatment at 450 MPa and 50 °C for 60 min was obtained as 9 ± 2.2%. The residual pectinesterase activity in orange juice after treatment at 450 MPa and 50 °C for 30 min was determined as approximately 7 ± 1.6%. It compares with 12 ± 0.2% at a treatment of 40 °C and 450 MPa for 60 min. Pressure resistant isoenzymes were thought to be responsible for the final residual activity. The inactivation is irreversible and the enzyme is not reactivated upon storage. High pressure processing constitutes an effective technology to inactivate the enzymes in fruit juices. Pressures higher than 400 MPa can be combined with mild heat (<50 °C) to accelerate enzyme inactivation.
Previous model studies have suggested ascorbic acid as one of the major sources of furan, a possibly hazardous compound found in thermally processed foods (e.g. canned products, jars). The study showed that about 2 mmol mol(-1) furan was obtained when dry-heating ascorbic acid, while much lower amounts were formed upon pressure cooking, i.e. 58 micromol mol(-1) at pH 4 and 3.7 micromol mol(-1) at pH 7. Model reactions also generated 2-methylfuran (MF). However, the MF levels were generally very low with the exception of the binary mixture ascorbic acid/phenylalanine (1 mmol mol(-1)). Studies with 13C-labelled ascorbic acid indicated that furan comprises an intact C4 unit, mainly C-3 to C-6, generated by splitting off two C1 units, i.e. CO2 and formic acid. Possible intermediates are 2-deoxyaldoteroses, 2-furoic acid and 2-furaldehyde, which are known as ascorbic acid degradation products. The mechanism of furan formation from ascorbic acid was validated based on the labelling pattern of furan and the identification of 13CO2 and H13COOH. Furan formation is significantly slowed down in binary mixtures, e.g. the presence of erythrose led to 80% less furan under roasting conditions. This is most likely due to competing reactions in complex systems, thus disfavouring furan formation. The mitigation effect is because furan, contrary to MF, is formed without recombination of ascorbic acid fragments. Therefore, furan levels are definitely much lower in foods than expected from trials with pure ascorbic acid. Consequently, conclusions should be drawn with much caution from model reactions, avoiding extrapolation from oversimplified model systems to food products.
The current work monitored a wide range of quality attributes of purée based on kiwifruit (Actinidia deliciosa, ‘Hayward’) during the final phase of ripening. A targeted approach was used to analyze texture, color, sugar, acidity and activity of specific enzymes. A headspace gas-chromatography mass-spectrometry analysis was used as an untargeted approach to fingerprint the volatile fractions. A multivariate data analysis approach was used combining all quality parameters (targeted and untargeted) in order to determine the most important attributes changing during late ripening. This work demonstrated that hardness, color, sugars, acids (malic and ascorbic acid) and esters and aldehyde headspace compounds were the quality indicators, changing most during kiwifruit late ripening. During late ripening, hardness decreased significantly and soluble solids content increased. The color of kiwifruit purée turned dark and less green. Sucrose decreased significantly with glucose and fructose increasing accordingly. Titratable acidity and major organic acids (quinic and citric acid) showed a similar trend increasing at start of late ripening stage and then decreasing, however malic and ascorbic acid consistently decreased during ripening. Pectin methylesterase and β-galactosidase increased and then declined, whereas peroxidase consistently increased. The formation of esters, such as methyl hexanoate and ethyl hexanoate, and a decrease of aldehydes, like hexanal, heptanal and (E)-2-hexenal, was observed. Therefore, the present work clearly demonstrated the potential of the multivariate approach to zoom into important quality indicators for the final phase of kiwifruit ripening. The outcome can provide useful information for ripening stage evaluation of kiwifruits in the processing industry.
Shelf life of Golden Delicious apple juice treated by ultrahigh hydrostatic pressure (HPP) was evaluated in terms of colour, total polyphenol content, antioxidant capacity, ascorbic acid content, pH, titratable acidity, total soluble solids, polyphenol oxidase (PPO) activity, pectin methylesterase (PME) activity and sensory testing. Using response surface methodology it was determined to process the apple juice in a HPP unit at 430 MPa for 7 min, and stored at room temperature (20 °C) and in refrigeration (4 °C) for 34 days. No significant changes (p < 0.05) in physicochemical properties, nutritive value or sensory attributes were detected in the treated apple juice, but the PPO started recovering its activity during the storage without causing significant difference (p < 0.05) in its colour. PME was completely inactivated in the HPP treatment, while indigenous micro-biota of the raw juice was also eliminated. The applied processing conditions preserved the physicochemical and sensory quality of apple juice, and kept polyphenols content and antioxidant capacity unaltered.
Typical apple (Malus domestica Borkh.) flavour develops during ripening. Maximum endogenous volatile concentration occurs at the climacteric peak but it is not known whether the volatile biosynthetic enzymes are constitutive or induced during the climacteric. Exposing apples to hypoxic conditions induces accumulation of high concentrations of acetaldehyde and ethanol; after return to air ethyl esters are enhanced and non‐ethyl esters decrease. There are differences in degree of ethyl ester enhancement among cultivars. These may be because of: differential activity or synthesis of alcohol acyl CoA transferase (AAT) or alcohol dehydrogenase (ADH); separate iso‐forms of AAT and ADH each with their own substrate specificity; variation in alcohol precursors in different cultivars; or a combination of all three. Volatile production is greater at higher temperatures in the range from 0 to 30°C but exposure to low temperatures (
The effects of high hydrostatic pressure and thermal processing on blanched and unblanched mango nectar were addressed by headspace GC-MS fingerprinting as an untargeted approach. Comparison between high hydrostatic pressure and thermal processing was performed based on the principle of equivalence. A considerable number of volatiles with higher concentrations were observed in unblanched mango nectar compared to blanched mango nectar. Both for high hydrostatic pressure and thermal processing, changes of mango nectar volatiles (composition and concentration) became more pronounced upon increasing processing intensity. However, based on a fair comparison, different process-induced chemical changes were detected for high hydrostatic pressure and thermal processing. For unblanched mango nectar, thermal processing seems to favor the formation of sulfur-containing compounds (dimethyl sulfide), whereas high hydrostatic pressure seems to enhance the oxidation of free fatty acids, leading to increased concentration of aldehyde and alcohol volatile compounds (1-penten-3-ol, (Z)-2-penten-1-ol, and (E)-2-pentenal) in mango nectar. For blanched mango nectar, less significant differences were found between high hydrostatic pressure and thermal processing. This work demonstrates that different processing steps, for example blanching, high hydrostatic pressure, and thermal processing, have influence on the volatile profiles of the processed products.
High-pressure (HP) destruction kinetics of three common spoilage microorganisms, Zygosaccharomyces bailii, Pichia membranaefaciens and Leuconostoc mesenteroides, and two pathogenic microorganisms, Escherichia coli O157:H7 and Listeria monocytogenes Scott A, were evaluated in processed mango juice at pressures ranging between 250 and 550MPa and a hold time 0-60min at 20-25C with genera-specific initial counts in the 10 6 to 10 8cfu/mL range. Microbial destruction was evaluated based on (1) an initial kill which is due to a pressure pulse (pulse effect) and (2) a subsequent semi-logarithmic destruction during the pressure hold time. The decimal reduction times were genera-specific and decreased with an increase in pressure. Pressure sensitivity of microbial destruction rate was evaluated by a z P value. L. mesenteroides was found to be most resistant spoilage bacteria; yet its complete destruction was achieved by a 5-min treatment at 400MPa. Pathogenic E. coli was the most resistant of all the bacterial strains tested. A six-log reduction in E. coli O157:H7 was observed at 400MPa when treated for 10min, while at 500 and 550MPa, there were no survivors after the 1-min treatment. HP processes were established using a 6, 8 and 10D treatment based on E. coli O157:H7, and counts were monitored after treatment and during subsequent storage at 20, 12 and 4C for 28days. Results showed that these processes were satisfactory because no growth of E. coli O157:H7 was observed during the entire storage time.
To get deeper insight into the effect of high pressure high temperature (HPHT) processing on the volatile fraction of carrots, differently coloured cultivars exhibiting orange, purple, red and yellow hues were investigated. The impact of HPHT sterilisation was compared with thermal sterilisation based on equivalent microbiological inactivation. The results of this study demonstrated HPHT sterilisation to exert a distinct effect on important chemical reactions in comparison to thermal sterilisation. A comprehensive integration of MS-based metabolomic fingerprinting (HS-SPME–GC–MS) and chemometric tools has been implemented as an untargeted multivariate screening tool to identify differences. In all carrot cultivars, two dominant discriminative quality-related reactions were found: oxidative degradation and the Maillard reaction. Regarding the first reaction, oxidative terpenes, free fatty acids and carotenoids degradation products were detected at higher levels after HPHT sterilisation. Regarding the latter reaction, HPHT sterilisation appeared to suppress the formation of Maillard and Strecker degradation products.
To improve the flavour quality of bayberry juice, effects of different raw materials, heat treatment and storage time on the flavour variations were investigated. Changes of total sugar and titratable acids were also monitored. Identification and quantitation of volatile flavour compounds were performed by headspace solid-phase microextraction couped with gas chromatography–mass spectrometry (HS-SPME–GC–MS). The contents of esters, alcohols, total sugar and titratable acidity of the rancid flavour raw juice were 6.03%, 8.24%, 5.56 g/L, 0.18 g/L less than those of pleasing flavour raw juice (PF), while the content of aldehydes was 4.19% higher than that of PF. After 9 months storage, the bayberry juice produced fermentation-like flavours with alcohols increases (11.45%) while esters (14.91%) and total sugar (3.27 g/L) decreases. The results suggested that proper juice processing and storage techniques are critical to the flavour quality of bayberry juice.
Response surface methodology was used to evaluate the optimal high pressure processing treatment (300-500MPa, 5-15min) combined with Stevia rebaudiana (Stevia) addition (0-2.5% (w/v)) to guarantee food safety while maintaining maximum retention of nutritional properties. A fruit extract matrix was selected and Listeria monocytogenes inactivation was followed from the food safety point of view while polyphenoloxidase (PPO) and peroxidase (POD) activities, total phenolic content (TPC) and antioxidant capacity (TEAC and ORAC) were studied from the food quality point of view. A combination of treatments achieved higher levels of inactivation of L. monocytogenes and of the oxidative enzymes, succeeding in completely inactivating POD and also increasing the levels of TPC, TEAC and ORAC. A treatment of 453MPa for 5min with a 2.5% (w/v) of Stevia succeeded in inactivating over 5 log cycles of L. monocytogenes and maximizing inactivation of PPO and POD, with the greatest retention of bioactive components.
This paper describes a method for quantifying food appearance and studies the relationship between colour appearance and sensory characteristics of expected levels. Orange juice is used as an example. An experiment involving visual assessments was carried out using a calibrated digital display. The first phase of the experiment (i.e. Phase I) focused on investigating tolerance for colour as an orange juice attribute and the second phase (i.e. Phase II) concentrated on relationships between juice colours and expected sensory characteristics. Visual judgements were made of sourness, sweetness, bitterness, flavour strength and freshness. In Phase I, 174 juice colours were rendered systematically in CIELAB colour space and assessed by 15 observers. It was found that colour tolerance of orange juices can be determined using the CIELAB colour difference formula (ΔEab∗). A colour will be accepted by the majority as natural orange juice if its colour difference against an ideal juice colour is smaller than 12.60 ΔEab∗ units, where the lightness, chroma and hue of the ideal orange juice colour was 67, 62 and 88°, respectively. In Phase II, observers were asked to assess the same panel of stimuli using the expected levels of the five sensory characteristics. It was found that greenish juice colours elicited greater sourness and bitterness responses. Darker juice colours were more likely to be expected to be bitter, and redder and yellower juice colours were expected to be sweeter and have stronger flavour. Fresher juices were distributed within the region of saturated yellow. These relationships were described by means of ΔEab∗ which reasonably explains the relationships except the cases of sourness (R2 = 0.66) and freshness (R2 = 0.66). A new colour difference formula ΔEOJ was proposed and this formula effectively improved the performance of predictions for sourness (R2 = 0.72) and freshness (R2 = 0.82). The methodology developed in this study includes a systematic study to find the “ideal” colour appearance of a particular food, application of the psychophysical method for assessing expected levels of different sensory characteristics and a method for modelling the appearance and expectation relationships. This methodology can be widely applied to optimise visually perceived expectations for other foods and products that are sensitive to visual judgements of quality.
Consumers demand foods that are easy to consume and that are of high nutritional and sensory quality. Therefore, they appreciate the similarity of minimally processed products to fresh products. In recent years, the food industry has shown increased interest in nonthermal preservation technologies, because they provide products of proven quality and can be an alternative to traditional thermal methods, thus increasing added value. This review examines the effects of high pressure processing (HPP) on the nutritional and physicochemical parameters of fluid foods. While some general trends can be observed, the effects of HPP differ not only according to treatment intensity, but also according to the food matrix, suggesting that each matrix should be studied separately.
The effects of thermal treatments on 11 °Brix apple puree were studied at temperatures from 80 to 98 °C. Colour changes (measured by reflectance spectroscopy, colour difference, L*, a* and b* and the evolution of 5-hydroxymethylfurfural (HMF) and sugars (hexoses and sucrose) were used to evaluate non-enzymatic browning. A kinetic model based on a two-stage mechanism was applied to the evolution of colour difference and a*. A first-order kinetic model was applied to L* evolution, while the evolution of absorbance at 420 nm (A420) of the liquid fraction was described using a zero-order kinetic model. Thermally treated samples became more reddish and suffered a slight loss of yellow hues. The effect of temperature on the kinetic constants was described by an Arrhenius-type equation. The presence of pulp in the samples led to activation energies for A420 and sucrose which were lower than those found previously for clarified juices with the same soluble solids content.© 2000 Society of Chemical Industry
The ‘Charm’ analytical procedure was applied to several apple cultivars and replication gave almost identical charm responses. However, no two cultivars showed close resemblance by the technique. Charm response can be used, together with physical parameters, to describe apple flavour.
The aim of the present study was the evaluation of the physicochemical, nutritional and microbial quality of acidified Granny Smith (GS) apple purée processed on industrial-scale high pressure system during 3 weeks of refrigerated storage (5 °C ± 1 °C). Two commercially feasible pressure treatments (400 and 600 MPa/5 min/20 °C) and a mild conventional pasteurization at 75 °C/10 min, with pasteurization values of P70°C7.5 = 8.15 min, were conducted and their effect on total vitamin C (total Vit C), ascorbic acid (AA) and total phenolic content (TPP), and on instrumental quality parameters (color, viscosity, soluble solids, titratable acidity and pH) were comparatively studied. Inactivation of indigenous microorganisms (total aerobic mesophilic and psychrotrophic counts and moulds and yeasts) of the apple product was also studied and monitored during storage. Total Vit C and AA contents were unaffected by the 400 MPa and the mild pasteurization treatment. TPP content was not changed during processing at 400 MPa, but was affected by the 600 MPa and also slightly by the pasteurization treatment. Experimental data on the loss of total Vit C during storage were described with a first-order reaction kinetic and times of half loss between 9.3 to 10.3 days could be estimated for the three studied processes. Storage provoked loss of TPP content and color deterioration of pressurized GS puree samples, which was attributed to enzymatic browning reactions. Microbial counts were reduced by the different preservation techniques below the detection limit (50 cfu g−1) and storage revealed no further growth.
In this article an experimental approach is applied to determine the impact of High Hydrostatic Pressure (HHP) processing (350 to 550 MPa at 20 °C and for 1 to 25 min of holding time) on the survival of Issatchenkia orientalis and the spoilage of apple juice (with 300 ppm added ascorbic acid) during different storage conditions, i.e., 4 to 12 °C and 0 to 36 days of storage. Probabilistic modelling approaches based on logistic regression models were developed in order to describe quantitatively the spoilage/no spoilage and survival/death interfaces. For a microbially stable processed apple juice treated at 400 MPa, 10 °C and a holding time of 15 min the degradation kinetics of vitamin C were described quantitatively during subsequent storage at 4, 8, 12 °C. The rate of vitamin losses were highly reduced after the first 13 days of storage. The stability of the apple juice with respect to browning and cloudiness was evaluated by studying qualitatively the activity of polyphenol oxidase (PPO), and pectin methyl esterase (PME) enzymes at combined treatments of HHP and temperature (10 to 50 °C, HHP at 750 MPa and holding time from 1 to 25 min). The highest achieved reduction of PPO and PME was 51.47% and PME 81.44%, respectively.Industrial relevanceThis paper demonstrates an approach based on quantitative probabilistic and qualitative studies for defining the stability interfaces of apple juice. Its applicability contributes on the design and optimisation of High Hydrostatic Pressure treatments.
The effect of high hydrostatic pressure on ester formation and hydrolysis was studied. Six esters and the corresponding carboxylic acids and alcohols were subjected to high-pressure treatments of 400 and 800 MPa under three different pH conditions (namely, buffer solutions of pH 4, 6 and 8). The selected compounds were dissolved into buffer solutions, subjected to the pressure treatment and then extracted using dichloromethane. The analysis and quantification were carried out by gas chromatography with flame ionization as detector. High pressure appeared to have no effect on ester formation or hydrolysis under the investigated conditions. In all cases, a small decrease at the levels of carboxylic acids and esters was observed without any evidence of further reaction. This decrease, referred to as decomposition, depended on pressure and pH conditions. Ester decomposition was minimised when a high-pressure treatment of 400 MPa in basic conditions (pH 8) was applied. Carboxylic acid decomposition was minimal in basic conditions and it was independent of the pressure applied.
We compared the eating quality of a new apple cultivar, ‘GoldRush,’ with ‘Golden Delicious’ (one of its parents), ‘Fuji,’ and ‘Granny Smith’ (the latter two often used for fresh-cut apple slices). We also compared a commercial with an in-house processing treatment, NatureSeal for apples and Produce Quality and Safety Laboratory (PQSL), respectively. Intact apples that had been stored for about 6 months were washed, processed into fresh-cut slices, stored, and then served to consumers. Both NatureSeal and PQSL treatments maintained cut-surface color values similar to values at the time of cutting. NatureSeal-treated slices were rated slightly better for texture than those receiving the PQSL treatment, but there was no significant difference in acceptability of appearance or flavor. Acceptability scores for the texture and flavor of ‘GoldRush,’ and of ‘Fuji’ when included, were higher than those of ‘Granny Smith’ and ‘Golden Delicious.’ There were small age and gender biases, with older women liking ‘GoldRush’ less and older men liking ‘Granny Smith’ less than other age groups and cultivars in one study. No instrumental measurement was a satisfactory predictor of sensory acceptability scores. ‘GoldRush’ proved to be a promising new cultivar for fresh-cut apple slices and the in-house processing solution maintained the quality of apple slices similar to that of a commercial processing treatment.
Standard quality parameters, consumer acceptance, and volatile compound emission of ‘Pink Lady®’ apples (Malus × domestica Borkh.) were measured at harvest and after 14 and 25 weeks of cold storage in three different atmospheres. After storage, fruit were left to ripen for 1 and 7 days at 20 °C before instrumental and sensory measurements were performed. Data were subjected to principal component analysis (PCA) and partial least square regression (PLSR). PLSR results indicated that the parameters positively influencing acceptability were soluble solid content, titratable acidity, background colour, and emission of hexyl 2-methylbutanoate, hexyl hexanoate, hexyl propanoate, butyl 2-methylbutanoate, 2-methylbutyl acetate and butyl propanoate. Results of sensory analyses revealed the treatments considered in this work could be split into two levels of acceptability.
In 2004, the US-FDA announced the findings of its exploratory surveys of furan in selected foods. In the 3 years since, there have been a number of publications on furan in foods. This review looks at furan in foods, its metabolism and toxicity. The important factor of heating is explored along with the precursors and chemical mechanisms that may be involved. Finally, prospects for limiting the occurrence, formation and retention of furan in foods are discussed.
High hydrostatic pressure (HHP), pulsed electric fields (PEFs), ultrasound (US), and cold plasma (CP) are emerging technologies that have already found application in the food industry or related sectors. This review aims to describe the basic principles of these nonthermal technologies as well as the state of the art concerning their impact on biological cells, enzymes, and food constituents. Current and potential applications will be discussed, focusing on process-structure-function relationships, as well as recent advances in the process development.
Food pasteurized by hydrostatic high pressure have already been marketed in Japan. There is great interest in this method also in Europe and USA. Temperature and pressure are the essential parameters influencing the state of substances including foods. While the influence of temperature on food has been extensively investigated, effects of pressure, also in combination with temperature, are attracting increasing scientific attention now. Processes and reactions in food governed by Le Chatelier's principle are of special interest; they include chemical reactions of both low- and macromolecular compounds. Theoretical fundamentals and examples of pressure affected reactions are presented.
EU of the European Parliament and of the Council amending Council DirectiveEC relating to fruit juices and certain similar products intended for human consumption
Directive 2012/12/EU of the European Parliament and of the Council amending
Council Directive 2001/112/EC relating to fruit juices and certain similar
products intended for human consumption. (2012). Official Journal of the European Union, L115, 1e11.
Directive 2012/12/EU of the European Parliament and of the Council amending Council Directive 2001/112/EC relating to fruit juices and certain similar products intended for human consumption
- D G Cunningham
- T E Acree
- J Barnard
- R M Butts
- P A Braell
Cunningham, D. G., Acree, T. E., Barnard, J., Butts, R. M., & Braell, P. A. (1986). Charm
analysis of apple volatiles. Food Chemistry, 19(2), 137e147.
Directive 2012/12/EU of the European Parliament and of the Council amending
Council Directive 2001/112/EC relating to fruit juices and certain similar
products intended for human consumption. (2012). Official Journal of the European Union, L115, 1e11.