Weeks Of Cold Storage Research Articles

Effect of the transition between ethylene and air storage on post-harvest quality in six UK-grown potato cultivars

SummaryLong-term storage of potato (Solanum tuberosum L.) tubers provides year-round availability of the crop, but is limited by sprouting. Continuous exposure to ethylene during storage can prolong the storage-life of potato tubers by suppressing sprouting, yet there is little information on the effects of ethylene on a wide selection of common cultivars. Six different UK potato cultivars were stored at 6ºC for 30 weeks under continuous 10 µl l 1 ethylene treatment, under continuous air, or transferred from air to 10 µl l 1 ethylene at the first indication of sprouting, or vice versa. Fructose, glucose, and sucrose concentrations were determined in samples of tuber flesh and in potato skins. Texture and sprouting were measured after 30 weeks in cold storage. Ethylene applied at the first indication of sprouting was as effective at suppressing further sprouting in ‘Desiree’, ‘Sylvana’, and ‘Fianna’ as observed when ethylene was applied continuously and resulted in no additional ethylene-induced sugar accumulation. The texture data suggested that ethylene treatment had an indirect effect on tuber firmness through the inhibition of sprout growth only in ‘Sylvana’ potato tubers. The implications of these results are that the cost of ethylene application in cold-store rooms could be reduced by manipulating the timing of its application.

From optimization of synbiotic microparticles prepared by spray-drying to development of new functional carrot juice

Lactobacillus casei loaded chitosan-Ca-alginate microparticles enriched with the prebiotic fructooligosaccharide were prepared using spray-drying method associated with the polymers complexation and cross-linking with calcium. The concentrations of the formulation factors of alginate, chitosan and CaCl2 were optimized using 23 full factorial design. Experiments showed that microparticles with favorable physicochemical properties and high probiotic viability during preparation and storage could be obtained when 40 mg/g sodium alginate, 5 mg/g chitosan and 50 mg/g CaCl2 is used. Stability of L. casei during microencapsulation was identified by FTIR spectroscopy. The viability of the probiotic in the optimal formulation of synbiotic microparticles remained above the therapeutic minimum during incubation of 24 hours in simulated gastrointestinal conditions (7.67?0.4 log cfu/g) as well as after 3 months of cold storage (8.1?0.6 log cfu/g). High viability of L. casei was maintained during 6 weeks of cold storage when carrot juice was enriched with encapsulated cells. The effective preservation of L. casei into synbiotic microparticles provided production of new non-dairy functional food as an alternative of the population who is at risk of lactose intolerance.

Quality Change in Plug Seedlings of Three Indigenous Medicinal Plants after Short-term Cold Storage

To test the quality change of seedlings of three domestic medicinal plants raised in plug trays, a short term storage experiment was conducted. Seedlings were kept in growth chambers for two weeks at 4 or <TEX>$8^{\circ}C$</TEX> temperature combined with 0 or <TEX>$5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX> PPFD. Quality of glasshouse-raised seedlings was assessed after two weeks of cold storage in the growth chamber and one week of acclimation in the greenhouse. After two weeks of storage in the growth chamber of Perilla frutescens var. acuta Kudo, plant height was the greatest in the treatment <TEX>$8^{\circ}C$</TEX> combined with <TEX>$0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX> PPFD. Internode length of P. frutescens var. acuta Kudo was the greatest in the treatment of <TEX>$4^{\circ}C$</TEX> combined with <TEX>$0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX> PPFD. After one week of acclimatization in a glasshouse, the growth and development, such as plant height, internode length and leaf size, were greater in the <TEX>$8^{\circ}C$</TEX> combined with <TEX>$5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX> PPFD than in the other treatments. After two weeks of storage in the growth chamber of Sophora tonkinensis, plant height increased more in the treatment of <TEX>$4^{\circ}C$</TEX> than <TEX>$8^{\circ}C$</TEX>. After one week of acclimatization in a glasshouse, number of leaves did not change in the treatment of <TEX>$4^{\circ}C$</TEX> combined with <TEX>$0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX> PPFD, but it increased in the other treatments. Leaf width increased more under the dark than light condition. Leaf length did not observably change in any treatments. After two weeks of storage in the growth chamber, plant height of Angelica gigas Nakai was the greatest in the treatment of <TEX>$8^{\circ}C$</TEX>. Number of leaves was the greatest in the treatment of <TEX>$8^{\circ}C$</TEX>. Leaf growth was greater under dark than light condition. These results suggested that optimal storage environment was <TEX>$8^{\circ}C$</TEX> combined with <TEX>$5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX> PPFD for P. frutescens var. acuta Kudo, and <TEX>$4^{\circ}C$</TEX> combined with <TEX>$0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX> PPFD for S. tonkinensis and A. gigas Nakai. Hence, proper combination of temperature and PPFD were necessary for better storage, and acclimatization and growth, thereafter, of the plug seedlings of theses plant species.

Effect of cold storage and shelf life on physiological and quality traits of early ripening pear cultivars

Similar to other species, pear storage is cultivar-specific such that many early ripening cultivars often have limited storability. The effect of cold storage (2°C) on the qualitative traits of six summer pears (Pyrus communis L., namely cvs. “Carmen”, “Coscia”, “Etrusca”, “Precoce di Fiorano”, “Tosca” and “Turandot”) was investigated. The physical–chemical (weight loss, firmness, soluble solid content and titratable acidity) and sensory (fruit juiciness, sweetness, sourness, aroma, graininess and hardness) evaluations were performed after four, eight, 12 and 16 weeks at 2°C and after a five-day period at 20°C (shelf life). The maximum weight loss was recorded in “Precoce di Fiorano”, ranging from 3.6% to 6.0% after eight and 12 weeks of cold storage, respectively. Additionally, the titratable acidity (TA) was affected by the cold storage, and we observed some cultivar-specific changes. “Carmen” and “Tosca” showed a similar percentage decrease in the TA values compared to all other tested cultivars. A multivariate statistical approach, including a principal component analysis, reduced all datasets into three independent components, which accounted for 78.83% of the total variability and provided a global view of the early ripening pear cultivars in response to cold storage. “Precoce di Fiorano” showed rapid fruit decay as the cold storage period progressed; this cultivar preserved its physical–chemical and sensory traits only for a short cold storage period (i.e., four weeks), whereas “Etrusca”, “Carmen” and “Turandot” can be refrigerated for eight weeks with acceptable changes in their organoleptic characteristics. “Coscia” and “Tosca” showed the longest storability (i.e., 16 weeks).

Sweet Cherry Fruit Firmness and Postharvest Quality of Late-maturing Cultivars Are Improved with Low-rate, Single Applications of Gibberellic Acid

Sweet cherry (Prunus avium L.) producers in the Pacific Northwest have devoted considerable acreage to late-maturing cultivars. By using these cultivars to extend the harvest window, producers avoid lower returns associated with cherries harvested during the peak period (i.e., midseason) when supplies are overly abundant. Over several years, we evaluated preharvest applications of gibberellic acid (GA3) between 10 and 100 ppm (a.i.) on the late-maturing sweet cherry cultivars Lapins, Skeena, Staccato, and Sweetheart. Individual trials examined the timing of GA3 applications and/or rate on fruit quality attributes at harvest and after 4 weeks of cold storage at 0 °C. The influence of GA3 timing and/or rate on sweet cherry skin color and harvest delay was also evaluated. Multiple applications split between the end of Stage II (pit hardening) and mid-Stage III (final fruit swell) of fruit development did not improve fruit quality attributes or delay skin color development of ‘Skeena’ and ‘Sweetheart’ compared with equivalent concentrations applied once at the end of Stage II. Low concentrations (between 10 and 25 ppm) consistently improved fruit firmness (FF) of all cultivars by 10% to 43%. No further improvements in FF were observed when rates exceeded 25 ppm. Skin color development was retarded by GA3 but did not respond in a consistent manner to increasing rate. Fruit size was not uniformly increased by GA3. In trials where GA3 had a positive effect on fruit size, the effect was observed at low concentrations and was not further improved with increasing rate. A cultivar-dependent response to GA3 was observed for return bloom. ‘Skeena’ reproductive buds per fruiting spur and flowers per floral bud in years after treatment were unaffected by GA3 concentration. On the contrary, the number of flowers per bud of ‘Lapins’ was significantly reduced to 79% and 38% of control levels for 50 and 100 ppm GA3, respectively. At 100 ppm, GA3 additionally limited the number of reproductive buds returning on fruiting spurs of ‘Lapins’. GA3 reduced stem browning and surface pitting disorder of ‘Sweetheart’ and ‘Lapins’ after 4 weeks of cold storage at 0 °C; however, these effects were optimized at 25 ppm. Respiration rate and weight loss were unaffected by GA3 at harvest or after 2 and 4 weeks of cold storage. Unidentified endogenous factors that regulate FF and are inducible by GA3 appear to be largely responsible for improved resistance to pitting. Collectively, the results demonstrate high sensitivity of cherry FF and skin color to GA3. Split applications did not provide further harvest delays or affect any of the attributes evaluated, possibly because low rates (20 ppm) applied at the first timing were sufficient to saturate the response. In general, fruit quality of late-maturing cultivars of sweet cherry was improved by low rates of GA3 applied in a single application at the end of pit hardening.

Changes in sensory quality and aroma volatile composition during prolonged storage of ‘Wonderful’ pomegranate fruit

SummaryFlavour acceptance tests of ‘Wonderful’ pomegranate arils during prolonged storage under commercial modified atmospheres conditions yielded high preference scores during the first 12 weeks of cold storage at 7 °C, but sensory quality decreased remarkably after 16 and, especially, 20 weeks. Descriptive flavour analyses by a trained sensory panel revealed that the decrease in fruit flavour preference resulted mainly from a decrease in typical pomegranate flavour and increases in ‘overripe’ and ‘off‐flavour’ odours. GC‐MS analysis of aroma volatile contents revealed high correlations (r2 &gt; 0.9) between accumulation of the ethanol fermentation products ethanol and ethyl acetate and the observed decrease in fruit flavour preference. In addition, we observed relatively high correlations (r2 &gt; 0.7) between the accumulation of various sesquiterpene volatiles and the decrease in flavour preference. According to these findings, it is suggested that the decrease in flavour preference most likely resulted from massive accumulation of ethanol fermentation products and sesquiterpene volatiles.

Fortification of yoghurts with grape (Vitis vinifera) seed extracts

The feasibility of full-fat and non-fat yoghurts fortification with grape seed extracts from two grape varieties, namely Moschofilero and Agiorgitiko, was examined. Epicatechin, total phenolics, antiradical activity, reducing power, viable Lactobacilli counts and pH of fortified and not fortified yoghurts were followed throughout products' shelf life. The fortification of yoghurts at 5–10 mg gallic acid equivalents/100 g of yoghurt did not affect yoghurt pH and Lactobacilli counts and – as perceived by the authors during tasting – did not cause major defects in consistency, colour and flavour compared to controls; differences in colour were detectable by colorimetry. Seed polyphenols were detected in supplemented yoghurts, in amounts proportional to those of seed extracts. Fortified yoghurts contained more polyphenols and exhibited higher antiradical and antioxidant activity than controls, even after 3–4 weeks of cold storage. The degradation of polyphenols and the decrement of yoghurts' antiradical and antioxidant activities followed first order kinetics, with full-fat yoghurts exhibiting higher deterioration rates and lower half-lives than the non-fat ones. It is concluded that, at the supplementation levels tested, the production of functional yogurts with grape-seed antioxidants is feasible, given that the supplementation is carried out in the fermented product and not in milk prior to fermentation.

Preharvest Fungicide, Potassium Sorbate, or Chitosan Use on Quality and Storage Decay of Table Grapes.

Potassium sorbate, a program of four fungicides, or one of three chitosan formulations were applied to clusters of 'Thompson Seedless' grape berries at berry set, pre-bunch closure, veraison, and 2 or 3 weeks before harvest. After storage at 2°C for 6 weeks, the natural incidence of postharvest gray mold was reduced by potassium sorbate, the fungicide program, or both together in a tank mixture, in 2009 and 2010. In 2011, the experiment was repeated with three chitosan products (OII-YS, Chito Plant, and Armour-Zen) added. Chitosan or fungicide treatments significantly reduced the natural incidence of postharvest gray mold among grape berries. Berries harvested from vines treated by two of the chitosan treatments or the fungicide program had fewer infections after inoculation with Botrytis cinerea conidia. None harmed berry quality and all increased endochitinase activity. Chitosan decreased berry hydrogen peroxide content. One of the chitosan formulations increased quercetin, myricetin, and resveratrol content of the berry skin. In another experiment, 'Princess Seedless' grape treated with one of several fungicides before 4 or 6 weeks of cold storage had less decay than the control. Fenhexamid was markedly superior to the other fungicides for control of both the incidence and spread of gray mold during storage.

Changes in sugar and starch concentrations in parsnip (Pastinaca sativa L.) during root growth and development and in cold storage

SummaryLow-temperature sweetening of parsnip (Pastinaca sativa L.) roots, which may occur both pre-harvest and post-harvest, is a well-known phenomenon, but is poorly understood. ‘White King’ parsnip roots were analysed over two seasons (2008 and 2009) during field growth and over six months cold storage at 1ºC for their dry matter content, as well as their starch, sucrose, glucose, fructose, and malto-oligosaccharide (MOS) concentrations and for their changes in amylolytic enzyme activities (2009 only). In 2008, when the air temperature fell below 5ºC for 12 d in the last 8 weeks before harvest, the concentration of starch decreased significantly (P ≤ 0.05) and the concentration of total sugar increased significantly. In 2009, when temperatures did not fall below 5°C during the last 8 weeks before harvest, the concentrations of starch (339 + 17 mg g–1 DW) and total sugars (168 + 12 mg g–1 DW) did not change significantly. However, in both years, during 24 weeks in cold storage at 1ºC, starch levels were almost completely depleted, whereas sucrose concentrations and, to a lesser extent, MOS concentrations increased at least two-fold. Glucose and fructose concentrations also increased significantly during 24 weeks in cold storage, but to a much lower level than sucrose or MOS. Total amylolytic activity and α-amylase activity doubled during the first 8 weeks in cold storage, whereas β-amylase activity did not change significantly. As products of α-amylase activity, changes in MOS concentration paralleled the changes in α-amylase activity. The accumulation of sucrose and MOS may raise the culinary quality of cold-stored parsnip.

Survival of Bifidobacterium Lactis hn019 and Release of Biogenic Compounds in Unfermented and Fermented milk is affected By Chilled Storage at 4°C

Development of dairy products containing bifido bacteria is one of the main focuses in the food industry, considering the health benefits attributed to its survival through gut intestinal tract and the liberation of biogenic compounds. In order to evaluate the effect of process conditions on survival of Bifidobacterium animalis subsp. Lactis HN019 and release of biogenic compounds during cold storage two technological processes were employed: (i) addition of Probiotic (unfermented bifido milk; UFBM) and (ii) fermentation (fermented bifido milk; FBM). B. Lactis HN019 counts were stable only in fermented milks during seven weeks of cold storage. Moreover, dairy matrices associated with cold storage appeared to protect bifidobacteria during exposition to gastric conditions, assuring the correct Probiotic counts at gut entrance. The distribution of fatty acids was affected by the different Probiotic products. In contrast, fermentation process increased the relative contents of some bioactive fatty acids, such as elaidic acid (+11%) and conjugated linoleic acids (+20%). It was also noted an increase in polyunsaturated fatty acids in the FBM and a higher relative content of monounsaturated fatty acids in the UFBM, as compared to control milk. In addition, fermentation process by bifido bacteria enhanced the long chain fatty acids fraction in bifido milks as compared to control and unfermented bifido milks. Control milk and unfermented bifido milk showed the same peptides even after seven days of storage in contrast with fermented milks that had increase bioactive peptides. It is possible to suggest that opioid peptides are formed during fermentation process, increasing the source of bioactive peptides. Finally, the cold conservation process modified peptides and could improve antibacterial activity.

Role of Membrane Lipid Peroxidation, Enzymatic and Non-enzymatic Antioxidative Systems in the Development of Chilling Injury in Japanese Plums

Chilling injury (CI) is a major postharvest constraint in the long-term cold storage, transportation, and distribution of japanese plums (Prunus salicina). The aim of the work was to explain the development and severity of CI in japanese plums based on the oxidative stress theory following time course analysis of enzymatic and non-enzymatic antioxidants. Changes in membrane lipid peroxidation and enzymatic and non-enzymatic antioxidative systems in japanese plum cultivar Blackamber were determined at weekly intervals during 5 weeks of cold storage at 0 °C and at 2-day intervals during poststorage simulated shelf conditions (21 ± 1 °C) for 8 days after each week of cold storage. Fruit respiration and ethylene production rates showed typical climacteric patterns after removal from cold storage and these rates were relatively high after 4 and 5 weeks compared with 0 to 3 weeks of storage. The CI symptoms first appeared after 3 weeks of cold storage after fruit had been transferred to simulated shelf conditions. The incidence and severity of CI intensified with increasing storage duration. The extent of lipid peroxidation indicated by concentration of thiobarbituric acid-reactive substances and membrane damage manifested as electrolyte leakage increased with increasing duration of storage and subsequent simulated shelf conditions. Membrane lipid peroxidation exhibited positive correlation with the severity of CI. Activities of primary antioxidant enzymes and the enzymes involved in the ascorbate–glutathione cycle were determined to explain the levels of reduced and oxidized forms of cellular redox buffers, ascorbate and glutathione. In response to chilling stress, antioxidative protection systems operated efficiently during the first 3 weeks of cold storage, but extended storage resulted in loss of ability to ameliorate increasing levels of oxidative stress. In this study, the comprehensive analyses of various metabolites and antioxidative systems explain the series of events involved in development of CI in japanese plums in support of the oxidative stress theory.

MRI can reveal metabolic changes in lily bulbs in vivo during dormancy release

The factors influencing dormancy release in lily bulbs strongly affect commercialization success, but the mechanism of dormancy release is still unclear. Magnetic resonance imaging (MRI) can detect changes in morphology and water status in a living plant bulb and aid in investigating release factors. To evaluate whether MRI could be used to detect intra-bulb metabolic changes during the dormant period in Oriental Lilies (Lilium 'Sorbonne'), a series of MRI and sugar concentration measurements were performed weekly on bulbs stored for 11 weeks at 4°C. The image quality of intra-bulb structure obtained using T (1)-weighted imaging was superior to that obtained using T (2)-weighted imaging and had a higher signal-to-noise ratio (0.97 ± 0.01). Magnetization transfer ratio values for the bud and basal plate declined during the first eight weeks of cold storage (P>0.05), and were well correlated with concentration of soluble sugar in the bud (R (2)=0.95) and basal plate (R (2)=0.93). Thus, MRI can serve as a valuable tool for observation and analysis of dynamic morphological and metabolic changes in vivo during dormancy release. This information is potentially useful as a guide in the improvement of horticultural product quality.

Controlled and modified atmospheres influence chilling injury, fruit quality and antioxidative system of Japanese plums (Prunus salicina Lindell)

SummaryOur objective was to compare the effects of controlled atmosphere (CA) and modified atmosphere packaging (MAP) on fruit quality, chilling injury (CI) and pro‐ and antioxidative systems in ‘Blackamber’ Japanese plums. Matured fruit were stored for 5 and 8 weeks at 0–1 °C in normal air, CA‐1 (1% O2 + 3% CO2), CA‐2 (2.5% O2 + 3% CO2) and MAP (~10% O2 and 3.8% CO2). CA was more effective than MAP in retention of flesh firmness and titratable acidity during cold storage. Fruit stored in CA‐1 showed reduced CI and membrane lipid peroxidation after 5 and 8 weeks of cold storage. Low O2 atmospheres appeared to limit the generation of reactive oxygen species (ROS) and their efficient scavenging through the concerted action of superoxide dismutase and peroxidase. The role of ascorbate–glutathione (AsA–GSH) cycle in the regulation of oxidative stress was also studied during and after storage in different atmospheres. In conclusion, optimum CA conditions delayed fruit ripening and CI through augmentation of antioxidative metabolism and suppression of oxidative processes.

Effect of Preharvest Application of Methyl Jasmonate on Fruit Quality of Plum (Prunus Salicina Lindell cv. “Fortune”) at Harvest and during Cold Storage

Effects of two different methyl jasmonate (MeJA) doses, applied 2 weeks ahead of estimated harvest date, on fruit weight loss (%), color, firmness, total soluble solids (TSS), total phenolic (TP), total antioxidant activity (TAA) and individual phenolic compounds of “Fortune” plum were investigated at harvest and during 4 weeks of cold storage. Application of MeJA significantly increased weight loss at the end of storage period. entire color characteristics decreased linearly in all treatments during the storage period. The highest fruit firmness value at the end of storage was obtained from 1,120 mg L−1 MeJA treatment. TP and TAA values increased linearly in all treatments during the storage period. The highest post-storage total phenolics and antioxidant values was observed in the 2,240 mg L−1 MeJA application. MeJA applications significantly increased the chlorogenic acid content during the storage (P < 0.05). Practical Applications Plum fruits constitute a good source of natural antioxidant substances. Particularly, plums contain large amounts of phenolic compounds and flavonoids having natural antioxidant activity which is effective in human diet. results of the study indicated that there was a linear relationship between total phenolic and antioxidant activity.

Cold Storage of Rat Hepatocyte Suspensions for One Week in a Customized Cold Storage Solution – Preservation of Cell Attachment and Metabolism

Background & AimsPrimary hepatocytes are of great importance for basic research as well as cell transplantation. However, their stability, especially in suspension, is very low. This feature severely compromises storage and shipment. Based on previous studies with adherent cells, we here assessed cold storage injury in rat hepatocyte suspensions and aimed to find a cold storage solution that preserves viability, attachment ability and functionality of these cells.MethodsRat hepatocyte suspensions were stored in cell culture medium, organ preservation solutions and modified TiProtec solutions at 4°C for one week. Viability and cell volume were determined by flow cytometry. Thereafter, cells were seeded and density and metabolic capacity (reductive metabolism, forskolin-induced glucose release, urea production) of adherent cells were assessed.ResultsCold storage injury in hepatocyte suspensions became evident as cell death occurring during cold storage or rewarming or as loss of attachment ability. Cell death during cold storage was not dependent on cell swelling and was almost completely inhibited in the presence of glycine and L-alanine. Cell attachment could be greatly improved by use of chloride-poor solutions and addition of iron chelators. Using a chloride-poor, potassium-rich storage solution containing glycine, alanine and iron chelators, cultures with 75% of the density of control cultures and with practically normal cell metabolism could be obtained after one week of cold storage.ConclusionIn the solution presented here, cold storage injury of hepatocyte suspensions, differing from that of adherent hepatocytes, was effectively inhibited. The components which acted on the different injurious processes were identified.

The effects of cold storage and aminoethoxyvinylglycine (AVG) on bioactive compounds of plum fruit (Prunus salicina Lindell cv. ‘Black Amber’)

Effects of two different aminoethoxyvinylglycine (AVG) doses (100 and 200mgL−1), applied 2 weeks ahead of estimated harvest date, on fruit color (L*, C* and h°), firmness, total soluble solids content (TSSC), total phenolics (TP), total antioxidant activity (TAA) and individual phenolic compounds of ‘Black Amber’ plums at the time of harvest and during 4 weeks of cold storage were investigated. Color characteristics linearly decreased in all treatments during storage. Fruit firmness at the end of the storage period was significant decreased (P<0.05) with AVG treatments. TSSC rates linearly increased during the storage period although the differences among treatments were not significant. Both TP and TAA increased with all treatments until the 21st day of storage and decreased by the 28th day. TP and TAA were significantly decreased (P<0.05) with the 100mgL−1 AVG treatment at the end of storage. While chlorogenic acid, p-coumaric acid and rutin increased during storage, epicatechin, catechin, caffeic acid, ferulic acid and kaempferol linearly decreased. AVG treatments generally had negative impacts on individual phenolic compounds.

UTILIZATION OF CHILLPEACH MICROARRAY PLATFORM FOR COMPARING CHILLING INJURY-SUSCEPTIBLE 'HERMOZA' AND CHILLING INJURY-RESISTANT 'ODED' PEACHES

ISHS IV International Conference Postharvest Unlimited 2011 UTILIZATION OF CHILLPEACH MICROARRAY PLATFORM FOR COMPARING CHILLING INJURY-SUSCEPTIBLE 'HERMOZA' AND CHILLING INJURY-RESISTANT 'ODED' PEACHES

Identification of compounds characterizing the aroma of oblate-peach fruit during storage by GC-MS

Three analytical methods, including headspace solid-phase microextraction (HS-SPME), liquid–liquid extraction (LLE) and steam distillation extraction (SDE), were utilized to investigate the aroma profile characteristics of Xinjiang oblate-peach fruit during storage, and the characterizing compounds were detected by gas chromatography mass spectrometry (GC-MS). Silica fiber coated with (DVB-CAR-PDMS) was found to be more efficient for collecting the SPME headspace volatile compounds, and the extraction time of 40 min was preferred in this study. The SPME headspace volatile constituents present in oblate-peach before and after 4 weeks of cold storage (4±1°C) have been analysed, while some physical characteristics such as fruitweight, firmness, soluble solids content (SSC), and titratable acid were monitored during storage. The results show that the volatile compounds displayed different composition during storage, a total of 58 volatiles were identified, 52 prior to storage and 45 after 4 week’s storage, the content of lactones and esters, characteristic compounds of peach aroma, were much lower after 4 weeks of storage. Thirteen of the pre-storage volatiles were not found after storage. Key words: Oblate-peaches, aroma, gas chromatography mass spectrometry (GC–MS),headspace solid-phase microextraction (HS-SPME), liquid–liquid extraction (LLE), steam distillation extraction (SDE).

Improvement of the Cold Storage of Isolated Human Hepatocytes

Increasing amounts of human hepatocytes are needed for clinical applications and different fields of research, such as cell transplantation, bioartificial liver support, and pharmacological testing. This demand calls for adequate storage options for isolated human liver cells. As cryopreservation results in severe cryoinjury, short-term storage is currently performed at 2-8°C in preservation solutions developed for the storage of solid organs. However, besides slowing down cell metabolism, cold also induces cell injury, which is, in many cell types, iron dependent and not counteracted by current storage solutions. In this study, we aimed to characterize storage injury to human hepatocytes and develop a customized solution for cold storage of these cells. Human hepatocytes were isolated from material obtained from partial liver resections, seeded in monolayer cultures, and, after a preculture period, stored in the cold in classical and new solutions followed by rewarming in cell culture medium. Human hepatocytes displayed cold-induced injury, resulting in >80% cell death (LDH release) after 1 week of cold storage in University of Wisconsin solution or cell culture medium and 3 h of rewarming. Cold-induced injury could be significantly reduced by the addition of the iron chelators deferoxamine and LK 614. Experiments with modified solutions based on the new organ preservation solution Custodiol-N showed that ion-rich variants were better than ion-poor variants, chloride-rich solutions better than chloride-poor solutions, potassium as main cation superior to sodium, and pH 7.0 superior to pH 7.4. LDH release after 2 weeks of cold storage in the thus optimized solution was below 20%, greatly improving cold storage of human hepatocytes. The results were confirmed by the assessment of hepatocellular mitochondrial membrane potential and functional parameters (resazurin reduction, glucagon-stimulated glucose liberation) and thus suggest the use of a customized hepatocyte storage solution for the cold storage of these cells.

Chilling requirement for dormancy release of variegated Solomon’s seal

Dormancy release of variegated Solomon’s seal (Polygonatum odoratum Druce var. pluriflorum Ohwi for. variegatum Y.N.Lee) was studied by varying the transferring date from the field to greenhouse and by cold storage in order to identify their precise chilling requirement. Bud emergence and flowering did not occur throughout the experiment when dormant rhizomes were transferred until a calendar date November 22, 2009, in which natural cumulative chill unit (NCU) was 75 h. Days to sprouting, flowering, and flower abscission were shortened with delayed transferring dates. Percent sprouting and flowering showed an increasing tendency since rhizomes were transferred on December 7 (= 241 h NCU), but emergence date was not uniform. However, uniform percent sprouting was maintained since rhizomes were transferred on December 22 (= 492 h NCU). No or 1 week of cold storage at 0 or 5°C did not induce sprouting, which meant bud dormancy was not released when rhizomes were stored ≤ 1 week. When they were stored for more 2 weeks at 0 or 5°C, percent sprouting was increased to ≥ 91% in the heated greenhouse. Cumulative chill unit (CCU) was 336 h at 0°C and 225 h at 5°C. However, bud emergence date after 2 weeks of cold storage was not uniform at both storage temperatures, whereas bud emergence after 4 weeks of cold storage at 0°C was more uniform than that at 5°C. Therefore, at least 492 h NCU, 4 weeks of cold storage at 0°C (= 672 h CCU), or 6 weeks at 5°C (= 675 h CCU) is recommended for forcing and normal growth afterward of variegated Solomon’s seal.