Papers - ZUSHI Kazufumi
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Zushi K., Yamamoto M., Matsuura M., Tsutsuki K., Yonehana A., Imamura R., Takahashi H., Kirimura M.
Journal of the Science of Food and Agriculture 105 ( 2 ) 1159 - 1169 2024.9
Authorship：Corresponding author Publishing type：Research paper (scientific journal) Publisher：Journal of the Science of Food and Agriculture
BACKGROUND: Strawberry is a rich source of antioxidants, including ascorbic acid (ASA) and polyphenols, which have numerous health benefits. Antioxidant content and activity are often determined manually using laboratory equipment, which is destructive and time-consuming. This study constructs a prediction model for antioxidant compounds utilizing machine learning (ML) and multiple linear regression based on environmental, plant growth and agronomic fruit quality-related parameters as well as antioxidant levels. These were studied in three farms at two-week intervals during two years of cultivation. RESULTS: During the ML model screening, artificial neural network (ANN)-boosted models displayed a moderate coefficient of determination (R2) at 0.68–0.78 and relative root mean square error (RRMSE) at 3.8–4.8% in polyphenols and total ASA levels, as well as a high R2 of 0.96 and low RRMSE at <3.0% in antioxidant activity. Additionally, we developed variable selection models regarding the antioxidant activity, and variables two and five (environmental parameters and leaf length, respectively) with high accuracy were selected. The linear regression analysis between the actual and predicted data of antioxidants in the ANN-boosted models revealed high fitness with all parameters in almost all training, validation and test sets. Furthermore, environmental parameters are essential in developing such reliable models. CONCLUSION: We conclude that ANN-boosted, stepwise and double-Lasso regression models can predict antioxidant compounds with enhanced accuracy, and the relevant parameters can be easily acquired on-site without the need for any specific equipment. © 2024 Society of Chemical Industry.
DOI： 10.1002/jsfa.13906
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Postharvest changes in texture profiles and pectin metabolism in salt-stressed tomato Reviewed
Zushi K., Hojima M., Higashijima M.
Scientia Horticulturae 336 2024.10
Authorship：Corresponding author Publishing type：Research paper (scientific journal) Publisher：Scientia Horticulturae
In tomato cultivation, applying salt stress has been found to enhance organoleptic qualities. The texture of the tomato fruit is a crucial factor in determining quality and shelf life. However, postharvest changes in fruit texture of tomato grown under salt stress have not been studied. The study aimed to explore these changes and their relationship with pectin content and the activity of pectin-metabolizing enzymes. Salt stress was induced through addition of 100 mM NaCl to the nutrient solution, and ripe fruits were stored at 5 °C for 14 days. The loss of fruit weight after storage was consistent in both control and salt-stressed fruits, salt stress reduced the loss of fruit firmness by 36 % compared to control fruit. Salt-stressed fruits exhibited minor postharvest changes in several texture profiles compared to control fruits. Moreover, the mitigation of postharvest texture softening in salt-stressed fruits varied across different fruit tissues. Salt stress 40 % to 100 % increased the pectin content, which remained high during storage. Additionally, pectin-metabolizing enzymes like pectin methylesterase (PME) and polygalacturonase (PG) activities were 140 % and 80 % increased by salt stress, respectively; however, PG activity decreased during storage in salt-stressed fruits. The adhesiveness of the pericarp tissue was correlated with water-soluble pectin, PME, and PG. Therefore, we conclude that salt stress may mitigate postharvest texture softening, and the higher pectin content and pectin-metabolizing enzymes may contribute to this reduction in texture softening during storage in salt-stressed fruits. These findings suggest that salt stress could be a viable method for enhancing the texture and shelf life of tomatoes.
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Nakamura T., Zushi K.
Acta Horticulturae 3 ( 1404 ) 841 - 848 2024.9
Authorship：Last author Publishing type：Research paper (scientific journal) Publisher：Acta Horticulturae
Lutein is an antioxidant known to promote good health, and it is found in high concentrations in spinach leaves. Spinach is grown specifically for frozen processing in certain regions of Japan. However, there is a limited understanding of variation factors that affect the lutein content of spinach for frozen processing. Therefore, to gain a better understanding of these factors, we analyzed the relationship between the lutein content of spinach, environmental conditions, growth traits (flower bud differentiation, leaf numbers, plant height and weight, SPAD value, and sugar content), and chlorophyll a fluorescence OJIP transients to identify the factors that influence the lutein content. During the cultivation period (October 13, 2020 to April 1, 2021), lutein content, growth traits, and OJIP parameters were measured every month until flowering. Air temperature, solar radiation, and photoperiod increased from February until the end of the measurement period. Lutein content was approximately 6.6 mg 100 g-1 from November to January, but it decreased significantly to 3.5 mg 100 g-1 in February and March. Although the lutein content did not correlate with all of the growth traits, the period during which the lutein content decreased was coincident with the period from the flower bud differentiation of an apical meristem to bolting. Furthermore, the maximum fluorescence intensity in the OJIP was the highest in February, and the energy dissipation flux of the OJIP parameters was the highest in February. Therefore, the development of flower buds and the high energy dissipation in the photosynthetic apparatus with increased solar radiation may decrease in lutein content in February and March. In conclusion, we found that the development of flower buds may contribute to the decrease in lutein content and that the OJIP parameter may serve as an indicator of variation in the lutein content of spinach for frozen processing.
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ZUSHI Kazufumi, SUEHARA Chisato, SHIRAI Minori
Environment Control in Biology 62 ( 2 ) 49 - 56 2024.4
Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists
Ascorbic acid (AsA) is an essential phytonutrient, and tomatoes are an important dietary source. Tomato fruit AsA content is regulated by light conditions and is cultivar-dependent, but their regulations is unknown about the role of source-sink relationships. This study was designed to compare the light/dark-controlled regulation of AsA between intact (plant-attached fruits with source-sink relationships) and <i>in vitro</i> culture (plant-detached fruits without source-sink relationships) tomato fruits of five cultivars. Compared with fruits grown under light conditions, AsA content was lower in both intact and <i>in vitro</i> fruits grown in the dark; however, the decrease in AsA in the dark treatment was markedly lower in intact fruits (17-29%) than <i>in vitro</i> fruits (44-74%) and was dependent on the cultivar. Antioxidant enzyme activities and lipid peroxidation were lower under the dark condition in <i>in vitro</i> fruits (30-90%) but not intact fruits. Therefore, the reduction of AsA content under darkness occurred due to decreased <i>in situ</i> biosynthesis and antioxidant system activity in fruit without source-sink relationships. Furthermore, the reduction of AsA content induced by darkness was mitigated by source-sink relationships, as indicated by the intact fruit results, and their effects depend on cultivars.
DOI： 10.2525/ecb.62.49
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Nakamura Takeshi, Zushi Kazufumi
Horticultural Research (Japan) 23 ( 4 ) 261 - 269 2024
Authorship：Last author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE
Lutein, known for its health benefits, is abundant in spinach (<i>Spinacia oleracea</i>); however, factors influencing its concentration remain unclear in spinach for processing. Therefore, in this study, the relationships between the variation in lutein concentrations with the season and developmental stages, and agronomic parameters, such as weather conditions, growth traits, and chlorophyll a fluorescence OJIP transients (OJIP transients), were investigated. Spinach was cultivated until flowering in autumn and winter sowing. Seasonal variation in the lutein concentration was categorized into increasing and decreasing phases. The concentration increased at low temperatures and decreased at the optimal growth temperature, indicating a negative correlation with atmospheric temperature. During the increasing phases, OJIP transient levels (Fv/Fo) decreased due to chilling stress–induced growth inhibition. During the decreasing phases, prolonged chilling stress over 2 months led to reductions in OJIP transient levels, such as the performance index and Fv/Fm. Notably, initiation of the decreasing phase coincided with the flower stalk elongation period. This suggests a direct effect of atmospheric temperature on the lutein concentration in spinach, with flower stalk elongation potentially contributing to lower concentrations. Furthermore, OJIP transients emerged as potential indicators for monitoring the lutein concentration in spinach for processing.
DOI： 10.2503/hrj.23.261
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品種，成長および気象要因が加工・業務用ホウレンソウにおけるルテイン含量に及ぼす影響 Reviewed
中村剛, 八代賢, 永吉嘉文, 圖師一文
園芸学研究 22 ( 4 ) 287 - 294 2023.10
Authorship：Last author Language：Japanese Publishing type：Research paper (scientific journal)
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ZUSHI Kazufumi, TAKITA Kohei, EGAWA Ritsuki
Environment Control in Biology 61 ( 2 ) 37 - 43 2023.4
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists
Deficit irrigation can be used to improve tomato fruit quality. The semi-determinate tomato behaves like a bush tomato, with lateral shoots providing additional vegetative growth, but the response to deficit irrigation and the suitable training method have not been properly understood. Therefore, we clarify the combined effect of a training method (non-training, which omits manual plant management such as lateral shoot removal) and deficit irrigation (30–36% of field capacity) on yield, growth, and fruit quality of semi-determinate cherry tomato. Although deficit irrigation influenced non-training plants more than single-training plants (a conventional method by removing all lateral shoots) owing to the lowest midday leaf water potential, both plants showed the same levels of maximum quantum efficiency of photosystem II and fruit yield under deficit irrigation. Furthermore, non-training plants produced the highest levels of total soluble solids, glucose, fructose, citric acid, malic acid, and ascorbic acid under deficit irrigation. These observations indicated that the increased concentrations of the abovementioned components occurred as a result of water shortage in the fruit when compared with single-training plants. We conclude that non-training is suitable for semi-determinate cherry tomato cultivation under deficit irrigation, and that this method can produce high-quality fruits while mitigating manual plant management.
DOI： 10.2525/ecb.61.37
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Tissue-dependent seasonal variation and predictive models of strawberry firmness Reviewed
Zushi, Kazufumi Yamamoto, Miyu Matsuura, Momoka Tsutsuki, Kan Yonehana, Asumi Imamura, Ren Takahashi, Hiromi Kirimura, Masaaki
Scientia Horticulturae 307 111535 2023.1
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Scientia Horticulturae
Firmness is an important quality factor in strawberries. We investigated the tissue-dependent seasonal variation in strawberry firmness in epidermis, cortex, and pith tissues, and also developed statistical predictive models for the seasonal changes in firmness using environmental conditions and fruit properties. The experiment was conducted at three locations (sites A, B, and C) and in different harvesting seasons from winter (December) to spring (May) during 2 years. The fruit properties, including the total soluble solids (TSS), acidity, and fruit surface color decreased toward the end of the season (from winter to spring), with fruit harvested in April and May having the lowest values at all research sites. Similarly, the epidermis firmness decreased 0.73-fold toward the end of the season at all the research sites. The cortex firmness of site A showed a marked decrease of 0.64-fold toward the end of the season, but that of sites B and C remained at constant levels. The pith firmness tended to be higher for fruit harvested in December than in other months. We tested the training dataset using the stepwise multiple linear regression analysis to construct the statistical predictive models of firmness. The goodness-of-fit of the firmness predictive models, shown by the adjusted square correlation coefficient, was 0.47–0.54 in the model using the input data for daily mean environmental conditions several days before harvest as well as fruit properties, including fruit weight, color, and TSS. Additionally, in the regression analysis between predicted and actual values, the predictive models demonstrated accurate high performance with a low predictive error (0.06 as relative root mean square error). Thus, we concluded that strawberry firmness shows seasonal variation within the epidermis and pith tissues, and that their predictive models were of adequate accuracy and usefulness without the need for time-consuming, costly measurement equipment.
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Nakamura Takeshi, Yatsushiro Takeshi, Nagayoshi Yoshifumi, Zushi Kazufumi
Horticultural Research (Japan) 22 ( 4 ) 287 - 294 2023
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE
Lutein is an antioxidant with potential health benefits and is accumulated in spinach. However, little is known about the factors causing variations in the lutein content in spinach for processing. Thus, the effects of seasonal/cultivar variations, seedling thinning, and environmental conditions on lutein contents were investigated. The lutein content rose with increasing cultivation days, despite cultivation seasons. However, the lutein content interacted between cultivation days and cultivars in winter cultivation. A lower leaf water content under low temperatures may also enhance the lutein content. In addition, although plant growth, such as leaf/plant weight, was two-fold higher in thinning than in non-thinning plants, the lutein content was not affected by thinning. Furthermore, positive and negative interactions between environmental conditions and lutein contents were observed. The regression models between the lutein content and plant height/weight could be divided into two linear regressions according to plant development, such as whether the plant had started to bolt at harvest. Therefore, these results suggest the involvement of a decrease in the lutein content by flower bud differentiation/development. We conclude that the lutein content in spinach for processing is affected by cultivars, environmental conditions, and the developmental stage of the plant, such as flower bud differentiation.
DOI： 10.2503/hrj.22.287
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KIRIMURA Masaaki, TAKESHITA Shinichi, MATSUO Mitsuhiro, ZUSHI Kazufumi, GEJIMA Yoshinori, HONSHO Chitose, NAGAOKA Akira, NISHIOKA Kensuke
Environment Control in Biology 60 ( 2 ) 117 - 127 2022.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists
<p> In a sustainable society, it is necessary to develop systems that produce enough food and energy while also preserving the environment. Both agricultural production for food generation and photovoltaics for renewable energy production require large, open fields. In this research study, we investigate the feasibility of combining food and energy production into a single field by examining the effects of installing photovoltaic equipment above land used for farming. We grew komatsuna, kabu, mizuna, and spinach underneath photovoltaic equipment, and investigated the influence of shading from the photovoltaic equipment on plant growth and yields during winter cultivation. As expected, both the amount of solar radiation and the air and soil temperature were lower under the photovoltaics than those under the open field. The growth rate of komatsuna, kabu, and mizuna were slower. However, yields and qualities sufficient to meet market demands remained possible with extension of the cultivation periods. Therefore, although temperature and solar radiation are reduced under the photovoltaic equipment in winter, it is nevertheless possible to produce vegetables in the farmland, providing a novel opportunity to realize an integrated agricultural system with parallel production of food and energy.</p>
DOI： 10.2525/ecb.60.117
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Zushi K., Higashijima M.
Scientia Horticulturae 293 2022.2
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Scientia Horticulturae
Textural properties play an important role in the appreciation and acceptance of fresh tomatoes by consumers. This study aimed to clarify whether the effect of salt stress (50 and 100 mM NaCl) on texture profiles depends on the cultivars and/or tissue types of cherry tomatoes and visually identify the interactions of texture with organoleptic and consumer sensory properties using correlation network analysis. The effect of salt stress on texture profiles differed according to the cherry tomato cultivar, stress intensity, truss, and tissue (outer pericarp, locule, septa). The cohesiveness, gumminess, and chewiness of the outer pericarp and the cohesiveness of the locule were higher in salt-stressed fruit than in control fruit, but the effect was cultivar-dependent. Sensory properties such as overall taste, sweetness, and skin hardness and several organoleptic properties were 1.2–1.7-fold higher in salt-stressed fruit than in control fruit. Although no textural properties interacted with sensory properties in the control fruit network in correlation network analysis, the connectivity of textural properties such as cohesiveness with other traits in salt-stressed fruit increased with increasing salt stress intensity. In the network combining all treatments, the most connected node was cohesiveness, and cohesiveness was the key factor that enhanced the sensory and organoleptic properties of salt-stressed tomatoes, although the effects were cultivar- and tissue-specific. Thus, correlation network analysis provided visual insights into the interactions of textural properties with organoleptic and sensory properties.
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ZUSHI Kazufumi, FUKUDA Taiki, MORI Yudai, TAKAHASHI Hiromi, KIRIMURA Masaaki
Environment Control in Biology 60 ( 1 ) 91 - 101 2022.1
Authorship：Lead author, Corresponding author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists
<p> Seasonal variations of health-promoting properties of fruits have been known to depend upon environmental conditions and plant growth parameters; therefore, their trend lines need to be predicted. This study was aimed at finding out the impact of seasonal variations, induced by changes in the environmental conditions, to health-promoting properties of cherry tomato in long-term cultivation and at developing their statistical predictive models. Both total ascorbic acid content and antioxidant activity increased gradually during research period regardless the experimental site or year. Polyphenol content was the lowest at the initial date of study but it depended on experimental years. In addition, by the stepwise multiple linear regression analysis, we were able to develop a predictive model for health-promoting properties by using environmental data and plant growth/agronomic quality traits. In the best-fitted model, the combinations of data set and the data period were different for each compound. Furthermore, health-promoting properties can be predicted with high accuracy by using several environmental data 2 or 3 weeks before the harvest time and the growth/agronomic quality data at the harvest day. Thus, we conclude that constructed models may contribute to a good practice for the prediction of health-promoting properties of tomato.</p>
DOI： 10.2525/ecb.60.91
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ZUSHI Kazufumi, TSUTSUKI Kan, TAKAHASHI Hiromi, KIRIMURA Masaaki
Environment Control in Biology 59 ( 3 ) 147 - 155 2021.7
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists
<p> Strawberry (<i>Fragaria</i> × <i>ananassa</i> Duch.) is a rich source of diverse antioxidants associated with health benefits. However, the interactions of antioxidants with plant growth and photosynthetic performance have not been investigated in the strawberry fruit. This study aimed to visually identify the interactions of antioxidant compounds with plant growth, photosynthetic performance, and agronomic quality in commercially grown strawberry on three farms during a 2-month period using correlation network analysis. Growth and photosynthetic performance-related parameters showed variations between seasons and among farms, whereas antioxidant compounds showed only seasonal variations. Additionally, the total polyphenol content and antioxidant activity showed a negative correlation with ten and seven leaf photosynthetic performance parameters, respectively, but no correlation with any of the growth parameters. By contrast, ascorbic acid (ASA) and total ASA were correlated with two photosynthetic performance parameters and three plant growth parameters. These results suggest that ASA exhibits different interactions with the total polyphenol content and antioxidant activity. In addition, leaf thickness and several photosynthetic performance parameters were key factors of the interaction of antioxidant compounds. Overall, our results indicate that correlation network analysis provides useful information to enhance the level of antioxidant compounds in strawberry.</p>
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Zushi, K., Suehara, C., Shirai, M.
Scientia Horticulturae 274 109673 2020.12
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Scientia Horticulturae
The ascorbic acid (ASA) content of tomatoes is regulated by culture practices and environmental conditions such as light. However, in tomatoes, little is known about the direct effect of lighting conditions on ASA content in the absence of natural environmental fluctuations. The aim of this study was to determine the direct light regulation of ASA and dehydroascorbic acid (DHA) contents and the antioxidant system in tomato fruits grown in vitro using two different cultivars (high- and low-ASA cultivars), different light intensities [darkness, low light (∼249 μmol m−2 s−1), and high light (∼961 μmol m−2 s−1)], and different light spectra light emitting diodes (LEDs) under the same light intensity (226–249 μmol m−2 s−1): control (eight-peak LED), red LED light (peaks at 625 and 660 nm), and blue LED light (peaks at 420 and 450 nm). Results indicate that the effect of light on ASA and DHA content may be universal regardless of whether the cultivar is designated as a high- or low-ASA cultivar. ASA content was enhanced by an increase in light intensity and by blue (but not red) LED light. Our results also indicate that stimulation of the antioxidant system (ascorbate peroxidase and dehydroascorbate reductase activity) enhances ASA content under high light intensity, and underlying differences in mechanisms in response to blue and red LED light were observed. Therefore, we conclude that the direct light regulation of ASA content and the antioxidant system occurs in tomato fruits grown in vitro. In addition, our findings provide useful information for improving agricultural techniques to develop high-ASA tomatoes by controlling lighting conditions and by applying LED light.
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Using of chlorophyll a fluorescence OJIP transients for sensing salt stress in the leaves and fruits of tomato Reviewed
Zushi, Kazufumi, Matsuzoe, Naotaka
Scientia Horticulturae 219 216 - 221 2017.5
Language：English Publishing type：Research paper (scientific journal)
Salt is a major environmental stress to plant growth and productivity in tomato. Sensing salt stress is important to evaluate the degree of damage and the change in physiological condition in tomato plants. The aim of this study was to evaluate the salt stress in leaves and fruits in tomato using the chlorophyll a fluorescence OJIP transients (OJIP transients). Tomato plants were grown under various levels of salt stress (25, 50, 75, and 100 mM NaCl), following which we measured leaf stress indicators and OJIP transients in leaves and green fruits. In leaf stress indicators, the water potential decreased with increasing levels of salt stress, whereas the chlorophyll content (SPAD value) and the electrolyte leakage were not affected, except in 100 mM NaCl. The overall OJIP curves and each OJIP step in leaves decreased with increasing levels of salt stress, but were unaffected at the lowest level of salt stress (25 mM NaCl). Therefore, the OJIP curves were more sensitive indicators of salt stress in leaves than SPAD and electrolyte leakage. Conversely, in fruit, the OJIP curve was only significantly different in 100 mM NaCl compared with the control, and energy fluxes described by energy pipeline models were higher in 100 mM NaCl than in the control. These results indicate that, in severe salt stress such as 100 mM NaCl of fruit, JIP parameters and energy fluxes can show photosynthetic changes due to the increase in energy absorption efficiency of photosystem II against severe salt stress. Therefore, we conclude that OJIP transient analysis can be used as a non-destructive, simple, and rapid technique for sensing salt stress in tomato.
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Metabolic profile of organoleptic and health-promoting qualities in two tomato cultivars subjected to salt stress and their interactions using correlation network analysis. Reviewed
Zushi, K., Matsuzoe, N.
Scientia Horticulturae 184 8 - 17 2015.3
Language：English Publishing type：Research paper (scientific journal)
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Wajima Takahiro, Kondo Kensuke, Ichihara Yumiko, Kami Marie, Zushi Kazufumi, Shiratsuchi Hideki, Matsuzoe Naotaka
The journal of Junior College, Asahikawa University ( 45 ) 63 - 69 2015.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Asahikawa University
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Wajima Takahiro, Kondo Kensuke, Murayama Noriaki, Zushi Kazufumi, Matsuzoe Naotaka
The journal of Junior College, Asahikawa University ( 44 ) 33 - 40 2014.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Asahikawa University
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Light intensity modulates antioxidant systems in salt-stressed tomato (Solanum lycopersicum L. cv. Micro-Tom) fruits Reviewed
Zushi Kazufumi, Ono Makiko, Matsuzoe Naotaka
Scientia Horticulturae 165 ( 0 ) 384 - 391 2014.1
Language：English Publishing type：Research paper (scientific journal)
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Varietal differences in the chlorogenic acid, anthocyanin, soluble sugar, organic acid, and amino acid concentrations of eggplant fruit Reviewed
T. Mori T. Umeda T. Honda K. Zushi T. Wajima N. Matsuzoe
The Journal of Horticultural Science & Biotechnology 88 ( 5 ) 657 - 663 2013.9
Language：English Publishing type：Research paper (scientific journal)