Postharvest physiology
Abdollah Ehtesham Nia; Shirin Taghipour; Sara Siahmansour
Abstract
IntroductionWhile grapes are considered as non-climacteric fruits, during the post-harvest stages, due to the softening of the tissue, it is very prone to decay, which shortens its post-harvest life. Today, due to the desire of consumers to use high quality food, the use of biodegradable films and coatings ...
Read More
IntroductionWhile grapes are considered as non-climacteric fruits, during the post-harvest stages, due to the softening of the tissue, it is very prone to decay, which shortens its post-harvest life. Today, due to the desire of consumers to use high quality food, the use of biodegradable films and coatings with antimicrobial properties, is a suitable alternative to synthetic preservatives, in order to maintain food security and prevent wastage of significant capital. Edible coatings are edible thin layers that are used to increase the shelf life and quality of fruits. This material increases the quality and health of the product by creating a semi-permeable barrier to water vapor and oxygen and carbon dioxide gases between the product and the environment, and to prevent anaerobic respiration, it absorbs a certain amount of gases and to this Sequence increases product shelf life. One of the most important ways to increase the shelf life and maintain the quality of agricultural products, especially fruits, is the use of edible coatings on the crop surface. Chitosan is one of the most important natural derivatives of chitin, of which about 50% of its acetyl’s groups have been removed. Due to the fact that Aloe vera gel has no taste and odor, can be considered a good option as a cover for fruits after harvest and due to its elasticity and strength solution in water, as a suitable layer on the product. Located and protects the fruit from mechanical damage and moisture loss. Material and Methods In this study, 12-year-old mature grape trees of ‘Asgari’ cultivar in the scaffolding garden of Abestan region of Khorramabad city in 1398 were studied. In the pre-harvest stage, chitosan was sprayed on the tree and in the post-harvest stage, Aloe vera gel was applied by dipping the fruit in Aloe vera gel in the laboratory. After treatment, the fruits were stored in the refrigerator at a temperature of 4 ± 0.5 ° C and were examined at different time stages for quantitative and qualitative characteristics of the fruit. 20 identical grape trees (in terms of fruit size and load, with 50 to 70 annual branches in 8-14 buds) selected and grape clusters with different concentrations of chitosan (control (distilled water), 2 and 3 Percentage of chitosan) at different stages of growth (fruit set), 35 and 50 days later) were sprayed directly with 4 liters per vine, by hand sprayer (2 ml Tween 80% was added as the active surfactant). For this stage, immediately after harvesting the grapes, take them to the laboratory and immerse them in concentrations (zero, 25 and 33%) of Aloe vera gel for 10 to 20 seconds and then in the air. They dried. Then, grape fruits weighing about 360-300 g in each experimental unit were stored for 28 days at 4 ° C and examined. This study was performed as a factorial experiment (2 factors) in a completely randomized design with three replications. The first factor is the effect of the treatments studied in seven levels including: control, 2% chitosan (CTS 2%), 3% chitosan (CTS 3%), chitosan 2% + Aloe vera gel 25% (AVG 25% + CTS 2%), chitosan 3% + Aloe vera gel 25% (AVG 25% + CTS 3%), 2% chitosan + 33% Aloe vera gel (AVG 33% + CTS 2%), chitosan 3% + Aloe vera gel 33% (AVG 33% + CTS 3%) and the second factor was storage time at five levels (zero, 7, 14, 21 and 28 days after harvest). Data analysis was performed using SAS software and a significant difference between treatments for each trait with a minimum significant difference at the probability level = 0.05 α was determined. Results and Discussion The results of analysis of variance showed that the effect of treatment and storage time on the desired traits was significant at the level of one percent. Fruits treated with chitosan and Aloe vera gel had higher texture firmness, taste index, phenolic content, antioxidant activity and titratable acids and caries index and pH were lower than the control. The highest content of phenol, antioxidant, flavor index and titratable acidity in all five measurement times belonged to 2% chitosan treatments with both concentrations of Aloe vera gel (25 and 33%) and the lowest amount belonged to the control treatment. In control treatment, the percentage of caries index increased during storage and in grapes treated with chitosan and Aloe vera gel, the caries process was slower and the lowest rate of caries was observed in 2% chitosan treatment with aloe vera gel on the 14th day. In general, it was observed that pre-harvest application of chitosan and post-harvest Aloe vera gel increase the post-harvest life of ‘Asgari’ grapes and improve its quality traits. Chitosan creates a barrier with selective permeability to oxygen and carbon dioxide gases, and by placing carbon dioxide at a higher level and reducing oxygen, it creates a modified atmosphere around the fruit, which reduces respiration and ethylene production. As a result, it reduces the aging process and reduces the consumption of organic acids and sugars and prevents the increase of pH. Low pH prevents browning of the fruit due to the activity of catechins and chlorogenic acid enzymes. Aloe vera gel coating maintains and increases the antioxidant capacity of the whole fruit by reducing fruit juice loss, reducing respiration, reducing ethylene production and delaying aging. Conclusion The combined treatment of chitosan 2% and Aloe vera gel (25 and 33%) increased fruit firmness, titratable acidity, taste index, total phenol content and antioxidant activity of grapes and reduced pH and caries index. Application of these treatments increased the post-harvest life of ‘Asgari’ grapes by 14 days, so it can be stated that the use of chitosan in the pre-harvest stage and the use of Aloe vera gel in the post-harvest stage as biodegradable and natural compounds to increase Shelf life of ‘Asgari’ grape fruit is recommended.
Medicinal Plants
Shirin Taghipour; Abdollah Ehtesham Nia; Hamed Khodayari; Hassan Mumivand
Abstract
Introduction
Due to their pleasant and soothing taste and odor, attractive colors, and medicinal purposes, Chrysanthemum morifolium flowers have been widely used as food, tea, ornamentation, and medicine. It has been reported that C. morifolium can reduce hyperactivity of the liver, improve eyesight ...
Read More
Introduction
Due to their pleasant and soothing taste and odor, attractive colors, and medicinal purposes, Chrysanthemum morifolium flowers have been widely used as food, tea, ornamentation, and medicine. It has been reported that C. morifolium can reduce hyperactivity of the liver, improve eyesight and regulate cellular immunity. Pharmacological investigations have shown that Flo's chrysanthemum exhibits antibacterial, antioxidant, anti-inflammatory, and heart-protective characteristics. Previous phytochemical studies on caffeic acid derivatives, flavonoids, triterpenoids, glycosides and alkaloids have been isolated from Flo's chrysanthemum. In this study, chrysanthemum cultivars were evaluated in terms of having secondary compounds and desirable medicinal properties, as well as antibacterial effects to introduce superior cultivars and purposeful planning for breeding research. The purpose of the present study, 25 cultivars of C. morifolium were compared in terms of essential oil content, leaves total phenolic, flavonoid and antioxidant activity.
Materials and Methods
In this experiment, 25 chrysanthemum cultivars were studied in terms of essential oil percentage, antioxidant index, total phenol and flavonoid content and antibacterial effects in a randomized complete block design in Lorestan University research farm in the year 2016. Essential oil was extracted from dried flowers in the shade using a Clevenger apparatus for 3 hours. Evaluation of antioxidant activity of the extract was measured by DPPH method based on the method of Kulisic et al. (2004). The amount of flavonoids was measured by aluminum chloride and total phenol by Folin - Ciocalteu reagent colorimetric. Ward analysis was done to classify the cultivars.
Results and Discussion
The results of analysis of variance showed that the studied chrysanthemum cultivars had significant differences in terms of all studied phytochemical traits. According to the obtained results, among different cultivars, the total amount of phenolic compounds is between 14.52-47.90 mg/g dry weight, the total flavonoid content is between 11.59-55.62 mg/g DW and IC50 index varied between 83.92 and 257.43 μg/ml. The highest amount of total phenol was present in Avadis and Dila cultivars (45.86-47.90 mg/g dry weight), while Yasamin cultivar (14.52 mg/g DW) had the lowest amount. Also, in terms of total flavonoid content, Golnar and Farahnaz cultivars had the highest total flavonoid content with 55.62 and 53.01 mg quercetin/g DW, respectively. Cluster analysis divided all studied cultivars into five groups. The percentage of essential oil among different cultivars varied between 0.41 to 0.62% and a high variability was observed in terms of the amount of essential oil in the studied cultivars. The highest percentage of essential oil was related to Farhnaz and Elmira2 cultivars. In general, the results showed high antioxidant activity of most cultivars. Therefore, chrysanthemum extract can be introduced as a suitable source of natural antioxidants. Also in this study, Paridokht, Sana and Ashraf cultivars were studied in terms of antioxidant and antibacterial index and Farahnaz and Elmira 2 cultivars appeared superior to other cultivars in terms of essential oil production. Hedaei et al. (2018) studied evaluation of some bioactive compounds and antioxidant activity of leaf methanolic extract and flower essential oil content from different cultivars of Chrysanthemum morifolium, in this review, total phenol and flavonoid contents and IC50 values in different cultivars were ranged from 17.63-33.20 mg/g DW, 12.62-53.17 mg quercetin/g, and 54-228 μg/ml respectively. The highest phenolic content was in cultivar “Poya3” (33.20 mg/g DW), whereas the cultivar “Sahand2” (17.63 mg/g DW) contained the lowest value. Also, in terms of total flavonoid content, cultivars “Marmar” and “Sahand 2” had the highest and the lowest flavonoids with 53.17 and 12.62 mg quercetin per gram, respectively.
Conclusion
The results of the present study indicate a significant difference between different cultivars in terms of the total amount of phenolic, flavonoid and antioxidant compounds that the existence of such diversity can be the role of cultivar and genetics in the production of these compounds. According to the results of this study, chrysanthemum cultivars with desirable levels of phenolic and flavonoid compounds can be used as a source of natural antioxidants as an alternative to synthetic antioxidants. In this study, Sana, Paridokht and Ashraf cultivars appeared superior to the existing genotypes in terms of phytochemical and antibacterial traits. The results of this study can be used to select the correct parents for purposeful crosses in subsequent chrysanthemum breeding programs in order to improve the phytochemical traits of existing cultivars.
Pomology
Abdollah Ehtesham Nia; Shirin Taghipour; Sara Siahmansour
Abstract
Introduction: Table grapes (Vitis vinifera L.) is one of the most important fruits that is widely grown in the world and is the export fruit of many countries. Although edible grapes are classified as non-climacteric fruits, they are very prone to spoilage due to their softening, weight loss, and decay ...
Read More
Introduction: Table grapes (Vitis vinifera L.) is one of the most important fruits that is widely grown in the world and is the export fruit of many countries. Although edible grapes are classified as non-climacteric fruits, they are very prone to spoilage due to their softening, weight loss, and decay caused by fungi, as a result which consequently leads to low storability. Different strategies have been postulated to maintain firmness and control decay of table grapes during storage and improve functional properties of fruit such as pre and postharvest chitosan coatin, and exogenous abscisic acid application. Table grapes have a short shelf life due to the thin pericarp and fleshy texture of the fruit. Polyamines (PAs) application also showed a significant role in extending the storage periods of several fruit species with maintenance of fruit quality. Postharvest treatments are not necessarily the best way of maintaining fruit quality during postharvest period. Such treatments are expensive, increase the risk of fruit damage through extra handling and also encourage grower to pay less attention to on-tree quality. Pre-harvest application considered as a good alternative to cope with mentioned problem. To the best of our knowledge, there is not any report in literature about the role of pre-harvest application of Pas and post-harvest table grape in Aloe vera gel (AVG) as a possible role in reducing mechanical damage of berries which leads to lower decays. Besides these, damage caused by human handling starts at harvest operation, which still occurs by hand for most fruits.
Materials and Methods: This study was done on 12-year-old mature grape varieties of ‘Yaghouti’ in two independent experiments in the scaffolding garden of Abestan region of Khorramabad city and laboratory post harvesting of horticultural sciences department of Lorestan University in 2019. Therefore, this study investigated the effect of foliar application before harvesting of putrescine (PUT) in three different concentrations (0, 2.0 and 3.0 mM) and immersion post-harvest fruit in AVG (25.0 and 33.0%) on grape fruit quality and shelf life of table grape (Vitis vinifera cv. ‘Yaghouti’) in five times (0, 9, 18, 27 and 36 day) during storage at 4° C. The study was based on a factorial experiment with two pre-harvest spraying factors with PUT and post-harvest immersion in aloe vera gel (AVG) with three replications. The parameters of soluble solids (TSS), titratable acids (TA), ascorbic acid, total anthocyanin content (TCA), total phenol content (TPC), fruit firmness, shelf life of table grape (per day) were measured.
Results and Discussion: Fruits treated with both PUT concentrations showed greater firmness, vitamin C, total anthocyanin and phenol content, TSS, and during storage retained their shelf life longer than the control. At all five measurements, the highest levels of phenol and total anthocyanin content and firmness were related to the treatment of PUT 2.0 mM with coating of 25% and 33% AVG and the lowest was related to control. Also, pre-harvest use of PUT significantly prevented the softening of the fruit during storage and kept the firmness fruit. Softening contributes to quality loss in reducing the shelf life, but PAs treatment resulted in maintenance of flesh firmness during cold storage. Therefore, Put- and Spd-treated grape have higher firmness at harvest leading to much lower mechanical injury during harvest and handling process and providing better transportability. The purple skin color of table grape was related to the presence of anthocyanin compounds, from which the anthocyanin malvidin-3-glucoside has been found as major component. Although, total anthocyanins were reduced in control and treated fruits during cold storage, but pre-harvest foliar spraying of Put delayed total anthocyanins concentration after 36 days of storage and decreased the loss of these compounds at the end of experiment. PAs have been described as anti-senescence agents and a great number of researches have been focused on the role of exogenous PAs on fruit ripening. Also it has been reported that the ripening process and senescence of table grapes is correlated with the anthocyanin concentration and profile. However, the data on pre-harvest application of polyamine on different fruit species are scant. Khan et al., (2007) showed that pre storage application of Put would retard fruit softening in ‘Angelino’ plum during cold storage by suppressing ethylene biosynthesis. In mango, Malik and Singh (2005) reported that pre-harvest application of PAs improved fruit shelf life, increased ascorbic acid content and retarded fruit skin color changes compared to control
Conclusion: Pre-harvest foliar application of Put on grapevines maintained higher firmness at harvest and postharvest periods and also improved the fruit quality in terms of phenolics, ascorbic acid, anthocyanin and also controlling weight loss during cold storage. Overall, the results showed that pre-harvest use of 2.0 mM PUT and post-harvest immersion in 25.0% and 33.0% AVG improved the shelf life of the cultivar by 16 days compared to control.
Hassan Mumivand; Abdolhossein Rezaei Nejad; Shirin Taghipour; Kobra Sepahvand; Behnam Moradi
Abstract
Introduction: Drying is one of the most important post-harvest techniques for medicinal plants. Pelargonium graveolens (known as geranium) is an important, high-value perennial, aromatic shrub that can reach a height up to 1.3 m and a lateral growth of 1 m. The essential oil of P. graveolens is extensively ...
Read More
Introduction: Drying is one of the most important post-harvest techniques for medicinal plants. Pelargonium graveolens (known as geranium) is an important, high-value perennial, aromatic shrub that can reach a height up to 1.3 m and a lateral growth of 1 m. The essential oil of P. graveolens is extensively used in the perfumery and cosmetic industries. Medicinal plants produce antioxidant compounds, which defend cells against degenerative effects of reactive oxygen species produced during oxidative stress and metabolism. Antioxidants are molecules that scavenge free radicals and reduce/prevent their damages. Therefore, the identification of natural antioxidants as preservative agents plays a pivotal role for the food, cosmetic and pharmaceutical industry. This study was conducted to investigate the effect of different drying methods (microwave-drying, oven drying and ambient-drying) on drying time and some phytochemical properties of P. graveolens.
Material and Methods: In order to evaluate the effect of different drying methods on drying time and some phytochemical properties of Pelargonium, an experiment was conducted at the faculty of agriculture of Lorestan University (Khorramabad, Iran) in 2017. The experiment was carried out based on completely randomized design with 12 treatments and three replications. The drying treatments were microwave-drying (300, 600 and 900 watts), oven-drying (45, 55 and 65 °C), ambient-drying (shade-drying at room, shade-drying in the field, sun-drying for five hours and then transfer to the room shade, sun-drying for 10 hours and then transfer to the room shade, and sun-drying) and fresh samples (as control). In all drying methods, the drying process continued until the moisture content of samples reached to 12% based on dry matter.
Results and Discussion: The results of analysis of variance showed the significant effect of drying methods on total phenol and flavonoids contents, antioxidant activity and essential oil content of the plants. The minimum and maximum of drying time (4.05 min and 6 days, respectively) was related to microwave-drying (900 watts) and shade-drying in the field, respectively. The highest total phenol (14.78 mg GA per 100 g dry matter) and flavonoid (12.83 mg quercetin per 100 g dry matter) contents were observed in plants dried at room shade and field shade, while the highest antioxidant capacity (IC50=1.02) was related to the fresh samples. The plants dried in the oven (45 °C) also had a notable phenol and flavonoid contents with high antioxidant activity. On the contrary, the samples dried in the microwave and sunshine showed the lowest amount of phenol and flavonoid contents and antioxidant activity. The highest essential oil content was obtained from oven-drying at 45 °C (0.2 %w/w based on dry mater), followed by shade-drying in the field (0.17 %w/w based on dry mater), and oven-drying at 55 °C (0.15 %w/w based on dry mater). While, the lowest essential oil content occurred with microwave-drying at 900 W (0.04 w/w based on dry mater). In this study, the amount of essential oil in the microwave-drying plants was significantly reduced by increasing the power of the microwave. The decrease in essential oil content with increasing oven temperature was also observed. The decrease in essential oil content with increasing oven temperature has also been reported in other species such as peppermint, dill, tarragon and sage and could be due to evaporation of the essential oil along with moisture losing during drying process. The results of Hamrouni Sellami et al. (2012) showed that drying in microwave at 800 w increased total phenol and flavonoid levels of sage (Salvia officinalis L.). Their results showed that as the microwave power increased from 600 to 800 watts, the total phenol content increased significantly. In research by Arslan et al., (2010), the lowest total phenol content was observed in the oven dried samples, whereas the highest total phenol content was obtained from the oven-microwave treatment and sun drying. The researchers explained that this increase was probably due to the release of phenolic compounds during drying and the reason for the decrease in phenolic compounds in the oven was attributed to the high temperature. Besbes et al., (2004) also reported that with increasing drying temperature, the amount of total phenolic compounds decreases, which may be due to the destructive effect of high temperatures on phenolic compounds. In general, it could be concluded that drying in high temperature of oven and high power of microwave reduces the amount of phenolic and flavonoid compounds, antioxidant activity and essential oil content of P. graveolens. While, shade-drying and oven-drying at 45 °C showed the least reduction in these traits compared to the fresh samples.
Conclusion: It can be concluded that shade-drying at room, shade-drying in the field and oven-drying at 45°C are more suitable for the P. graveolens .While drying treatments in the microwave and sunshine are not suitable for the species. In addition, the results showed that there was a significant relationship between total phenol content and antioxidant activity in both assays.
