Yali Pear Research Articles

A study revealing mechanisms behind the stone cell of Yali pear degradation by mixed‐culture fermentation of lactic acid bacteria and yeast

AbstractThe presence of stone cells in pears is recognized as a problem for the pear processing industry. Bacillus and mold can degrade stone cells because of their potential to digest cellulose and lignin, but they cannot be used for the degradation test of pear stone cells. In this study Lactoplantibacillus plantarum JYLP‐326 was used in single culture or in the mixed culture with Saccharomyces cerevisiae Y2 to study their potential to degrade stone cells during fermentation and the mechanism of degradation was further explored. Synergy in cellulase activity was observed in the mixed‐culture where the maximum activity was observed at 96th hour of fermentation. Activities of endoglucanase, exoglucanase and β‐glucosidase were 1.75, 4.58, and 2.31. The degradation rate of stone cells in the mixed‐culture was 37.67%, which was significantly higher than that the results obtained for single cultures. The results of scanning electron microscopy (SEM) showed that the surface of the cultured stone cells became rough. Metabolomics studies confirmed the presence of specific metabolites related to the degradation of stone cells after the fermentation. It was concluded that the mixed‐culture fermentation using the above‐mentioned strains could be exploited by the pear processing industry to degrade stone cells.

Removal of aqueous vanadium(V) by green synthesized iron nanoparticles supported on corn straw biochar

Iron nanoparticles supported on corn straw biochar (PE-FeNPs@BC) were used to remove V(V). This material was prepared by using Yali pear peel extract-supported iron nanoparticles (PE-FeNPs) as the functional body and corn straw biochar (BC) as the support. The synthesis conditions such as Fe/C mass ratio and synthesis temperature were optimized. The material was characterized by SEM-EDS, FTIR, XRD, and XPS. The results showed that particle agglomeration was reduced, and the dispersion was improved after PE-FeNPs were supported on BC. The removal effect was better in the pH range of 2–6, and the removal efficiency was the highest at pH 3.7. At 25 ℃ and pH 3.7, the maximum adsorption capacity qm of V(V) was 362.7 mg/g, and 95.1 % of 90 mg/L V(V) was removed. The coexisting NaCl or NaNO3 had a weaker effect on the removal of V(V). The adsorption reactions followed the pseudo-second-order model and Langmuir model, and chemical adsorption was the dominant process. The main reaction mechanism of PE-FeNPs@BC with V(V) was as follows: adsorbed V5+ was reduced to V4+ by Fe0 and Fe2+ and then removed by co-precipitation in the forms of xFe2O3·yV2O5·zH2O and VO2·H2O. This study promotes the reuse of waste pear peel and can provide an environmentally friendly method for removing V(V) pollution.

Removal of Cr(VI) by iron nanoparticles synthesized by a novel green method using Yali pear peels extracts: optimization, reactivity, and mechanism

Removal of Cr(VI) by iron nanoparticles synthesized by a novel green method using Yali pear peels extracts: optimization, reactivity, and mechanism

Rapid and non-destructive decay detection of Yali pears using hyperspectral imaging coupled with 2D correlation spectroscopy

The black spot disease caused by Alternaria alternata on Yali pears is a great concern as it compromises their edible quality and commercial value. To realize rapid and non-destructive classification of this disease, hyperspectral imaging (HSI) technology was combined with two-dimensional correlation spectroscopy (2DCOS) analysis. A total of 150 pear samples at different decay grades were prepared. After obtaining the HSI images, the whole sample was demarcated as the region of interest, and the spectral information was extracted. Seven preprocessing methods were applied and compared to build the classification models. Thereafter, using the inoculation day as an external perturbation, 2DCOS was used to select the feature-related wavebands for black spot disease identification, and the result was compared to those obtained using competitive adaptive reweighting sampling and the successive projections algorithm. Results demonstrated that the simplified least squares support vector model based on 2DCOS-identified feature wavebands yielded the best performance with the identification accuracy, precision, sensitivity, and specificity of 97.30%, 94.60%, 96.16%, and 98.21%, respectively. Therefore, 2DCOS can effectively interpret the feature-related wavebands, and its combination with HSI is an effective tool to predict black spot disease on Yali pears. Keywords: hyperspectral imaging technology, black spot disease, two-dimensional correlation spectroscopy, Yali pear DOI: 10.25165/j.ijabe.20221505.7313 Citation: Zhang Y F, Wang W X, Zhang F, Ma Q Y, Gao S, Wang J, et al. Rapid and non-destructive decay detection of Yali pears using hyperspectral imaging coupled with 2D correlation spectroscopy. Int J Agric & Biol Eng, 2022; 15(5): 236–244.

Pengaruh Penambahan Asam Sitrat Terhadap Proses Non-Enzimatik Browning Jus Buah Pir Yali (Pyrus bretschneideri Rehd.)

The purpose of this study was to find out how effective citric acid is against the nonenzymaticprocess of browning Yali Pear fruit juice (Pyrus bretschneideri Rehd. Theresearch was conducted in a complete randomized design consisting of 5 replications. Thenon-enzymatic browning inhibition process was tested with citric acid treatment as the mainfactor with five concentrations ie 0% w/v, 2,5% w/v, 5% w/v, 7,5% w/v and 10% w/v.Qualitative parameters were dehydrogenase enzyme activity and reducing sugar level.Quantitative parameters were browning index and total soluble carbohydrate content.Levene test, analysis of variance, and Tukey test were performed at 5% significant level. Theresults showed that decrease in dehydrogenase enzyme activity occurs along with increasingthe concentration of citric acid. The level of reducing sugar has increased along with theincrease of citric acid concentration. The 7,5% w/v citric acid concentration effectivelyinhibited non-enzymatic browning of Yali Pear juice with a 21% reduction in the browningindex. Total soluble carbohydrate content increased 7% at 7.5% w/v citric acidconcentration. From the results of the study it was concluded that citric acid at 7,5% w / vconcentration was the inhibitor of non-enzymatic browning and dehydrogenase enzymeactivity, but stimulator of total soluble carbohydrate and reducing sugar level.

Effects of 1-methylcyclopropene and modified atmosphere packaging on fruit quality and superficial scald in Yali pears during storage

The Yali pear (Pyrus bretschneideri Rehd.) is susceptible to superficial scald during prolonged cold storage and at shelf life. This study investigated the effects of 1-methylcyclopropene (1-MCP) and modified atmosphere packaging (MAP) on changes of fruit quality and superficial scald during cold storage and at shelf life in Yali pear. Compared with MAP, the combination of MAP and 1-MCP (MAP+1-MCP) treatment reduced the carbon dioxide and ethylene content inside the packaging bag. The 1-MCP, MAP, and MAP+1-MCP treatments reduced the superficial scald index, malondialdehyde content, O2−· production rate and relative conductivity and inhibited the accumulation of α-farnesene and conjugated trienes in the peel. 1-MCP and MAP+1-MCP treatments maintained a higher phenolic content and enhanced the catalase and superoxide dismutase activities in the fruit, while reduced activities of lipoxygenase and polyphenol oxidase in the peel preceding the onset of superficial scald. Comprehensive analysis indicated that the MAP+1-MCP treatment is the most effective method tested for improving the quality of Yali pears during cold storage and at shelf life.

Hypobaric storage reduced core browning of Yali pear fruits

Core browning is a major issue of pear fruits. The primary factor leading to development of core browning is high levels of CO2 in storage. Hypobaric storage is a new postharvest technique to extend the shelf life of fruits and can reduce CO2 partial pressure. In this study, the effect of hypobaric storage on core browning of Yali pear fruits (Pyrus bretschneideri Rehd.) was evaluated. Results showed that fruits after 0.025MPa hypobaric treatment had 37.3% lower rate of core browning development and higher acidity and soluble solid content than control fruits. In addition, 0.025MPa hypobaric treatment increased activities of cytochrome oxidase (CCO) and peroxidase (POD), and 2,2-diphenylpicrylhydrazyl (DPPH) radicals and superoxide anion scavenging capabilities. In comparison with the control, hypobaric treated fruits had lower activity of polyphenol oxidase (PPO) and higher level of total polyphenols. Hypobaric treatment also reduced an increase of succinate dehydrogenase (SDH) and glucose-6-phosphate dehydrogenase (G-6-PDH) activities. Results indicated that hypobaric treatment could control core browning of pear fruits by regulating reactive oxygen species (ROS) generation and elimination enzymes to maintain cell membrane integrity and reduce enzymatic browning.

Comparison of the influence of defined storing conditions on asian and european pear cultivars

The study observed changes in the material composition of European (Conference) and Asian (Yali) pears during the storage period at different temperatures. Three different temperatures were selected for storing, i.e. 1 °C, 5 °C and 20 °C. Assessed for each of the pieces of fruit were flesh firmness, titratable acidity, soluble solids content, content of organic acids, and production of ethylene and carbon dioxide. Fruit stored at 1 °C and 5 °C was analysed before the moment of putting to the store and then after 25, 55 and 70 days of storing. Fruit stored at 20 °C was analysed before the moment of putting to the store and then after 14, 22 and 30 days of storing. The respiration intensity observed through carbon dioxide production at refrigeration conditions was approximately of the same progress for both of the varieties. For the Yali variety, the intensity of respiration of the fruit at the start of the storing period strongly decreased.The same progress was recorded for the Conference variety. Storing at 20 °C increased the respiration intensity. The varieties Yali and Conference which were stored under the temperature of 5 °C had the highest CO2 production after 70 days of storage. For both varieties the lowest ethylene production during storage was observed at 1 °C. Ethylene production was higher in Yali pear fruits. The Yali variety stored at 20 °C from the beginning produced up to 10 times higher concentration of ethylene than the fruit of the Conference variety. The highest amount of ethylen by the Conference variety was produced by the fruits which were stored under the temperature of 5 °C. At the beginning of the storage period the Conference pears had two-fold higher flesh firmness than the Yali fruit. Fruits of the varieties Yali and Conference which were stored 70 days under the temperature of 1 °C had the highest flesh firmness. For soluble solids and titratable acidity no clear progress was recorded. Malic acid was predominant in both varieties. The Yali fruit contained more citric acid than the Conference fruit. In both varieties soluble solids gradually increased in the early days of storage at all of the monitored temperatures.

Effects of nitrogen shock treatment on postharvest changes of Yali pears

ABSTRACTThe effects of short-term nitrogen (N2) treatment on fruit quality and respiratory enzymes of Yali pear (Pyrus bretschneideri Rehd.) were investigated. Fruit were N2 shocked by exposing them to N2 for 48 h, and then stored at 0–1°C under ambient atmospheric gas concentrations for 4 months. Results showed that titratable acidity (TA) and total soluble solids (TSS) contents in N2-shocked fruit were higher than those in control fruit. At the end of storage, the core browning rate in N2-shocked fruit was 29.9% lower compared to the control. Alcohol dehydrogenase (ADH) activity was inhibited by N2-shock treatment during the first 90 days of storage. In addition, N2-shocked fruit had lower succinate dehydrogenase (SDH) activity, while cytochrome c oxidase (CCO) activity was induced to high levels compared to the control. N2-shock treatment may be applied as an alternative technology to extend the shelf life of Yali pear fruit.

Effects of 1-methylcyclopropene on the physiological response of Yali pears to bruise damage

Yali pear (Pyrus bretschneideri Rehd.) is a fragile fruit and very susceptible to bruise damage. In this study, effects of 1-methylcyclopropene (1-MCP) on the physiological response of bruised Yali pears were investigated. Pears were treated with 10ppm 1-MCP before or after bruise damage, respectively, and then stored at 16°C. Results showed that 1-MCP treatments both before and after delayed the decrease of firmness, total soluble solids (TSS) contents and titratable acid (TA) contents in damage fruit. Bruise volume and L* value were also reduced by 1-MCP treatments. In addition, 1-MCP treated fruit had lower levels of hydrogen peroxide (H2O2) and superoxide radical production rate, associated with increased activities of catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidases (APX), as compared to the control. The protective effects of 1-MCP treatments on bruised fruits may be related to their ability to reduce and scavenge reactive oxygen species (ROS) by enhancing the antioxidant enzymes activity.

Effect of thymol on antifungal ability of chitosan coating against Penicillium expansum in Yali pear

In this work, we researched using thymol rather than complete EOs to improve antifungal effect of chitosan coating against P. expansum and the possible mechanisms of inhibiting the pathogen in pear. Our results showed that growth of P. expansum could be effectively inhibited both in vitro and in pear by thymol and resistance-related enzymes in pear also could be enhanced by it.

Cloning and expression analysis of an MYB gene associated with calyx persistence in Korla fragrant pear.

We isolated an MYB-like gene from Korla fragrant pear using differential display RT-PCR. Expression of this gene in flowers appears to be correlated with calyx persistence. Korla fragrant pear (Pyrus brestschneideri Rehd) is an economically important pear cultivar in China. A persistent calyx results in the deformation of the fruit. We used differential display RT-PCR to obtain 42 cDNA fragments from Korla fragrant pear flowers. Alignments of nucleotide and amino acid sequences suggested that two fragments (kfp1and kfp4) were related to calyx persistence. The fragments were 78% homologous with Malus × domestica SPL transcription factor (SPL3) and 83% homologous with Malus × domestica MYB transcription factor (MYB12). The complete cDNA sequence of kfpMYB was determined to clarify the role of MYB in calyx persistence. kfpMYB contained a 116 bp 5'-UTR, a 1122 bp open reading frame encoding 374 amino acids, and a 319 bp 3'-UTR. The nucleotide and amino acid sequences of the cDNA in Korla fragrant pear were highly homologous with those of MYB transcription factors in other plant species, suggesting that the sequence is a MYB transcription factor gene. The abundance of kfpMYB mRNA varied significantly between the second and fourth flowers on the branch. Furthermore, kfpMYB expression changed significantly during anthesis and was significantly higher in Jinfeng pear (persistent calyx) and Korla fragrant pear than in Yali pear (deciduous calyx). Expression of kfpMYB was significantly reduced by naphthalene (NAA), abscisic acid (ABA), PBO, and paclobutrazol (PP333). Uniconazole, ethylene (ETH), and gibberellic acid (GA3) had no signicant effect on kfpMYB expression. In conclusion, the expression of kfpMYB appears to be correlated with calyx persistence in Korla fragrant pear.

Effects of 1-MCP Treatment on the Ethylene Synthesis of Postharvest Yali Pear Seeds

The effects of 1-MCP treatment on the ethylene synthesis of Yali pear seeds of different harvest maturity were evaluated during storage. Yali pear fruit (early harvested and late harvested) were treated with 1.0 μL.L-11-MCP for 20 h at room temperature, packaged in PE plastic film and then stored at 0±1°C for 180 days. The results show that the respiration, ethylene production, ACC content, ACO and ACS activities of the seeds of early harvested Yali pear fruit with 1-MCP treatment decrease significantly during storage, the peaks decrease and are delayed for 60 days. But 1-MCP treatment has no significant effects on the indexes related with ethylene synthesis to the seeds of late harvested fruit. 1-MCP can be used to inhibit the synthesis of ethylene in the seeds effectively and keep the quality and extend the shelf life of early harvested Yali pear fruit.

Biochemical properties of oxidases of Yali pear

The biochemical properties of polyphenol oxidase (PPO), peroxidase (POD) and ascorbate peroxidase (APX) from Yali pear were investigated. The optimum pH and temperature of three enzymes was 5.6, 4.0, 7.0 and 20, 40, 50°C, respectively. Enzyme kinetics results showed that the Michaelis constant (Km) and maximum velocity (Vmax) of PPO for catechol were 0.22 M and 1111 U/ml/min. The Km and Vmax values of POD for guaiacol were 0.14 M and 1429 U/ml/min. The Km of APX for ascorbic acid and H 2 O 2 were 0.41 and 0.083 mM, respectively, and the Vmax of APX was 455 and 208 U/ml/min for ascorbic acid and H 2 O 2 , respectively. The inhibitory effects of the four inhibitors (ascorbic acid, citric acid, L-cysteine and phytic acid) on each enzyme were different, suggesting that the composite inhibitor is more appropriate for processing of Yali pear. Keywords: Yali pear, polyphenol oxidase, peroxidase, ascorbate peroxidase, biochemical property

Quality evaluation of mixed brewed perries based on PCA and sensory evaluation

In order to improve the sensory quality of Yali perry and choose fruits specially suitable for mixed fermentation with Yali pear, 11 kinds of fruits were selected and contrasted, including hawthorn, kiwifruit, Kyoho grape, Brown plum, Fuji apple, Nanguo pear, Dongzao jujube, Mopan persimmon, Korla pear, and Chi pear. These fruits were mixed separately with Yali pear, thus turning out 64 different types of mixed perries. The assessment on products was made based on the physiochemical indexes, aroma components via gas chromatography-mass spectrometry (GC-MS), and comparison between the qualities of the mixed perries via sensory evaluation and principal component analysis (PCA). Based on the PCA on the physiochemical indexes of 39 mixed perries and aroma components of 7 mixed perries, the models aiming at evaluating perry flavor and aroma quality were established, which were compatible with those of sensory evaluation; based on the sensory evaluation and PCA, hawthorn, plum, grape, and apple were suitable specially for mixing brewing, among which the hawthorn-Yali perry in the proportion of 25:100 and plum-Yali perry in the proportion of 40:100 scored the highest. The results will be helpful to the development of perry industry.

Construction and transformation for the antisense expression vector of the polyphenol oxidase gene in Yali pear

To inhibit the browning process in fruits of Yali pear, in this paper, antisense gene techniques were used to reduce the expression of PPO gene. A cDNA fragment of 450 bp, which is located at the 3′ terminal of the polyphenol oxidase (PPO) gene, was amplified from Yali pear using the RT-PCR method, then the antisense expression vector was constructed by inserting the fragment of the Yali pear PPO gene between the CaMV promoter and NOS terminator of the expression vector pBI121 in a reverse orientation. After that, with the agrobacterium-mediated method, the PPO antisense gene was transformed into Yali pear shoots. Northern blot analysis and enzyme activity assay showed that the PPO activities in the transgenic Yali pear shoots were significantly decreased, compared with the non-transformed Yali pear shoots. This lays a good foundation for breeding new varieties of pears with browning resistance in the future.

Use of UV‐C Treatment to Inhibit the Microbial Growth and Maintain the Quality of Yali Pear

The effects of UV-C radiation on microbial growth in vitro (Monilinia fruticola) and in inoculated Yali pears (Pyrus bretschneideri Rehd.) were investigated. Moreover, postharvest quality and the activities of defense and antioxidant enzymes were analyzed after the pears were exposed to UV-C irradiation at an energy level of 5 kJ m⁻².The results showed that spore germination of M. fructicola was significantly inhibited by each of the 3 doses (1, 5, and 10 kJ m⁻²) in vitro. In the in vivo assays, lesion diameter on the fruit being inoculated before or after the UV-C treatment was both significantly lower than that on the fruit of control. Meanwhile, the activities of phenylalanine ammonia lyase, β-1,3-glucanase, superoxide dismutase, catalase, and glutathione reductase were induced to high levels by UV-C treatment. We conclude that UV-C treatment could reduce postharvest disease by the germicidal and induced effects and maintain the quality by enhancing the antioxidant enzyme activities. UV-C radiation has recently been proposed as a new technology to avoid chemical fungicides. However, there are few studies regarding the effect of UV-C treatment on Yali pear. In this study, we found that 5 kJ m⁻² UV-C irradiation can control postharvest disease and maintain the quality of Yali pear. This method may be applied to reduce the decay of Yali pears during exporting and storage.

Effects of salicylic acid on the behavior of Yali pear infected by Alternaria kikuchiana Tanaka

To investigate the inductive effect of salicylic acid (SA) on the resistance of Pyrus bretschneider cv Yali to black spot disease (Alternaria kikuchiana Tanaka), the physiological and biochemical characteristics of detached pear leaves at the age of 5 to 10 days were measured after application of SA. The results showed that exogenous SA significantly improved the resistance of Yali pear (Pyrus bretschneider cv Yali) leaves to black spot disease. For the SA treatment at 0.02 mmol·L−1 SA concentration, the disease index was the lowest, and the induced resistance reached up to 63.9%. Furthermore, SA induced local and systemic resistance of Yali pear against the black spot disease. Expression of systemic resistance in leaves was detectable 3 d after SA treatments and lasted for 10 d. POD, PPO, and PAL activities of Yali pear leaves increased by SA treatment. It is suggested that exogenous SA solution as a chemical activator could induce the resistance of Yali pear to black spot disease.

Phenolic Compounds and Chromatographic Profiles of Pear Skins (Pyrus spp.)

A standardized profiling method based on liquid chromatography with diode array and electrospray ionization/mass spectrometric detection (LC-DAD-ESI/MS) was used to analyze the phenolic compounds in the skins of 16 pears (Pyrus spp.). Thirty-four flavonoids and 19 hydroxycinnamates were identified. The main phenolic compounds (based on peak area) in all of the pear skins were arbutin and chlorogenic acid. The remaining phenolics varied widely in area and allowed the pears to be divided into four groups. Group 1, composed of four Asian pears (Asian, Asian brown, Korean, and Korean Shinko), contained only trace quantities of the remaining phenolics. Yali pear (group 2) contained significant amounts of dicaffeoylquinic acids. Fragrant pear (group 3) contained significant quantities of quercetin glycosides and lesser quantities of isorhamnetin glycosides and the glycosides of luteolin, apigenin, and chrysoeriol. The remaining 10 pears (group 4) (Bartlett, Beurre, Bosc, Comice, D'Anjou, Forelle, Peckham, Red, Red D'Anjou, and Seckel) contained significant quantities of isorhamnetin glycosides and their malonates and lesser quantities of quercetin glycosides. Red D'Anjou, D'Anjou, and Seckel pears also contained cyanidin 3-O-glucoside. Thirty-two phenolic compounds are reported in pear skins for the first time.

Studies on browning problem and phenols content on shoots of Yali, Aikansui and Abbe Fetel pears for in vitro culture

Yali is one of the best pear cultivars cultivated extensively in China and other countries. However, mortality rates of explants during the initial phase of tissue culture were found to be very high during the summer particularly from the shoot tip explants. A thorough investigation on the browning problem of Yali Aikansui and Abbe Fetel pears was done and their control measures are suggested in this paper. Emphasis has been given to the Yali pear. Shoot explants were collected from the field as well as from the plantlets grown in vitro during different months and observed for browning. The explants were excised and cultured in Murashige and Skoog (MS) solid and liquid medium as needed. The cultures were maintained in the dark as well as in a 16/8 hours light/dark photoperiod regime as needed and were kept in a growth room at (25±2)°C temperature. According to the experimental results, Yali was found more severely infected by browning than the other two cultivars. Similarly, it was also found that, the intensity of browning was less during spring and increased with time and reached the maximum during summer. Shoot tips of Yali were found more severely infected by browning than the second node and other nodes. This accelerated the mortality rate up to 81% of shoot explants during the summer months of July and August. Browning was greatly influenced by water-soluble polyphenols, more of which were found in the shoot tip of explants collected from the field (significantly higher at P ⩽ 0.05 and P ⩽ 0.01). Total polyphenol contents were found less in the explants from plantlets grown in vitro, and less browning of medium appeared resulting in a lower mortality rate of explants. Collections of explants during early spring (P ⩽ 0.05 and P ⩽ 0.01) and use of other nodes rather shoot tip because explants (P ⩽ 0.05 and P ⩽ 0.01) were found to be better in preventing the browning problem. Finally, for curative measures to control browning, use of ascorbic acid at the rate of 100 mg·L−1 (P ⩽ 0.05 and P ⩽ 0.01), 0.02%polyvinyl pyrrolidone (PVP) in the culture medium (P ⩽ 0.05), 96 hours dark treatment of other nodes (P ⩽ 0.05), and 12 hours cold treatments of explants at 4°C (P ⩽ 0.05 and P ⩽ 0.01) prior to sterilization of explants, were found to be the best methods to control browning and therefore to increase the survival rate of cultured explants of the Yali pear.