Exogenous Melatonin Reduces Lignification and Retains Quality of Green Asparagus (Asparagus officinalis L.)

Asparagus (Asparagus officinalis L.) is highly perishable because of its high respiration rate, which continues after harvesting and leads to weight loss, increased hardness, color change, and limited shelf life. Melatonin is an indoleamine that plays an important role in abiotic stress. This study was designed to investigate the effects of melatonin on the quality attributes of green asparagus during cold storage. Green asparagus was soaked in a melatonin solution (50, 100, and 200 μM) for 30 min and then stored at 4 °C under 90% relative humidity for 25 days. The results indicated that melatonin treatment delayed the post-harvest senescence of asparagus and maintained high chlorophyll and vitamin C levels. Melatonin treatment hindered phenylalanine ammonia-lyase and peroxidase activities and reduced lignin content, thereby delaying the increase in firmness. Moreover, melatonin treatment enhanced catalase and superoxide dismutase activities, leading to reduced hydrogen peroxide content. These results indicate that melatonin treatment can be used to maintain the post-harvest quality and prolong the shelf life of green asparagus.

The microperforated packaging design and evaluation of shelf life of fresh-sliced mushrooms

Fresh mushrooms have a very short shelf life, of 1 – 3 days because of their high respiration rate and lack of cuticles that protect the plant from external factors. In the case of fresh-sliced mushrooms, they will be more susceptible to spoilage reactions due to the increase in respiration rate as a result of a broader surface area. Conventional packaging materials can not meet the requirements for modified atmosphere packaging of fresh-sliced mushrooms. One of the techniques to extend the fresh-cut produce shelf life is the passive modification of modified atmosphere packaging technology. For highly respiring fresh-cut produce such as fresh-sliced mushrooms, the permeability properties of the polymeric materials might not be enough to provide an equilibrium gas concentration in the passive modification of modified atmosphere technology. In this case, the microperforated packaging materials can be used for passive modification of fresh-cut produce. But the microperforation process needs a design for the application of the appropriate number and diameter of microholes to meet the requirements of passive modified atmosphere packaging. For this reason in this research, the design of the microperforation process to be used in passive modified atmosphere packaging was based on the diameter and the number of microholes, and the shelf life of fresh-sliced mushrooms was determined. The samples were stored at 15 °C/80% RH, and pH, color, weight loss, textural, sensorial, and microbial analysis were performed periodically during storage. It was determined that the empirical equation used in this research can be applied to microperforated packaging design for fresh-sliced mushrooms. The shelf life of the fresh-sliced mushrooms packaged with microperforated packaging material was 8 days, while it was less than 7 days (4, 5, or 6 days) when packaged with non-microperforated packaging material. This result shows that the use of microperforated packaging material is effective in extending the shelf life of fresh-sliced mushrooms.

Synergistic effect of calcium chloride and 1-Methylcyclopropene on storage of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai

Watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai was a climacteric variety with a high respiration rate and ethylene accumulation. Therefore the fruit matures and softeness quickly during post-harvest period. Calcium chloride was popularly utilized as stabilizing agent. 1-methylcyclopropene (1-MCP) has been known to be highly effective inhibitor of ethylene reaction. This research evaluated the synergistic effect of CaCl2 and 1-methylcyclopropene (1-MCP) treatment to weight loss, firmness, total soluble solid, carotenoid, ascorbic acid and decay rate of watermelon during storage. Results showed that a combination of 2.5% CaCl2 and 0.6 ppm 1-MCP in 20 min of immersion could extend watermelon shelf life for 15 days. After 15 days of ambient storage, the weight loss (1.43±0.02 %), firmness (4.38±0.00 N), total soluble solid (13.60±0.01 oBrix), carotenoid (16.31±0.02 µg/100g), ascorbic acid (13.36±0.03 mg/100g), decay rate (0.47±0.02 %) were clearly presented. Meanwhile, the treatment of 2.5% CaCl2 alone showed the weight loss (2.11±0.02 %), firmness (3.03±0.02 N), total soluble solid (10.83±0.02 oBrix), carotenoid (12.97±0.03 µg/100g), ascorbic acid (9.57±0.02 mg/100g), decay rate (2.14±0.01 %). The incorporation of CaCl2 and 1-MCP created a synergistic effect on the improved quality of watermelon fruit during ambient storage.

Non-Invasive Sheep Biometrics Obtained by Computer Vision Algorithms and Machine Learning Modeling Using Integrated Visible/Infrared Thermal Cameras

Live sheep export has become a public concern. This study aimed to test a non-contact biometric system based on artificial intelligence to assess heat stress of sheep to be potentially used as automated animal welfare assessment in farms and while in transport. Skin temperature (°C) from head features were extracted from infrared thermal videos (IRTV) using automated tracking algorithms. Two parameter engineering procedures from RGB videos were performed to assess Heart Rate (HR) in beats per minute (BPM) and respiration rate (RR) in breaths per minute (BrPM): (i) using changes in luminosity of the green (G) channel and (ii) changes in the green to red (a) from the CIELAB color scale. A supervised machine learning (ML) classification model was developed using raw RR parameters as inputs to classify cutoff frequencies for low, medium, and high respiration rate (Model 1). A supervised ML regression model was developed using raw HR and RR parameters from Model 1 (Model 2). Results showed that Models 1 and 2 were highly accurate in the estimation of RR frequency level with 96% overall accuracy (Model 1), and HR and RR with R = 0.94 and slope = 0.76 (Model 2) without statistical signs of overfitting

Effect of Nanostructured Chitosan/Propolis Coatings on the Quality and Antioxidant Capacity of Strawberries During Storage

Strawberries have a thin epidermis and a high respiration rate. The use of edible coatings containing chitosan nanoparticles (CSNPs) and propolis (P) has been effective in preserving the shelf life and antioxidant capacity of various fruit and vegetable products. The present research evaluated the effect of coatings with CSNPs and P on the quality, antioxidant compounds, and antioxidant capacity of strawberries. The specific coatings that were evaluated were chitosan (CS), CS+CSNPs33%, CS + CSNPs + P10%, CS + CSNPs + P20%, CS + CSNPs + P30%, and a control with no coating. The variables were weight loss, firmness, total soluble solids (TSS), color, phenols, total flavonoids, antioxidant capacity, and sensory characteristics. An ANOVA and a Tukey test (p ≤ 0.05) were used to analyze the data. Strawberries covered with CS + CSNPs + P10% showed the lowest weight loss (9.77%), while those covered with CS + CSNPs + P20% had the greatest firmness (4.96 N). CS + CSNPs + P coatings at 10%, 20%, and 30% concentrations maintained the antioxidant compounds and antioxidant capacity in the evaluated fruit (28.49 mg GAE g−1, 554.61 μg quercetin g−1, and 92.48% DPPH, respectively). The application of nanostructured coatings did not modify the sensory characteristics of the fruit. Coatings with CSNPs and/or P could therefore be a viable alternative for preserving the quality and antioxidant capacity of strawberries.

THE ROLE OF POTASSIUM AND CALSIUM IN IMPROVING THE QUALITY AND SHELF LIFE OF TOMATO (Lycopersicum esculentum var. servo)

Tomato has the characteristics natural to damage. Damage fruits are caused by destitute of fruit quality and sensory attributes. The loss of tomato production on harvest in developing countries reached 50% due to the long duration of tomato distribution. Servo varieties of tomatoes are in demand by farmers because of their genetic advantages, high productivity, and abundant fruit weights. The shortage of servo varieties of tomatoes is the short shelf life of fruit, which is seven days after harvest. Short shelf life is influenced by fruit thickness and fruit hardness. In improving the quality and shelf life of tomatoes, potassium (K) nutrition plays a role in photosynthetic translocation, strengthens the cell wall, and involved in the lignification process of sclerenchyma tissue. Tomatoes, as climacteric fruits have a high respiration rate influenced by ethylene. Ethylene production can be inhibited by calcium chloride (CaCl2) application by strengthening the cell wall mechanism, cross-link with pectin, and increase the cell wall regeneration can change the texture of the fruit become harder, and it reduces sensitivity to physiological damage. Based on the treatment of this research, the quality and shelf life of servo varieties of tomato is increased.

Effects of plant growth regulators on the in vitro flowering of carnation (Dianthus caryophyllus L.)

The flowering of terminal shoot of carnation has three stages: inflorescence, floral initiation and blooming. Respiration rate increased in the transition from the vegetative growth to the flowering and all the stages of flowering had high respiration rate. Auxin and gibberellin activities, the proportion of auxin to cytokinin increased, and the elongation of inflorescence stem began in the transition from the vegetative growth to floral initiation stage are involved. Auxin and cytokinin activity increased, the proportion of auxin to cytokinin and gibberellin activity decreased in the transition from the floral initiation to blooming stage. Most vegetative shoots became floral buds by two ways: one way induced by auxin with 0.25 mg/LIAA, and the other by cytokinin with 0.25 mg/L BA.

Physiological Changes of Torch Ginger (Etlingera elatior) Inflorescence during Development

The present study was undertaken to reveal the developmentally regulated changes in physical and physiological characteristics of torch ginger (Etlingera elatior) inflorescence in relation to its usage as a cut flower. The inflorescences at four developmental stages, i.e., tight bud (TB), six reflexing tip (SRT), all involucral bracts unfolded (IBU), and full bloom (FB) were studied. The results revealed that the fresh and dry weights of inflorescences increased significantly from TB to FB stage. Water was the main component of inflorescence with 90.8% to 91.9% of the total mass. Thus, cell expansion resulting from water influx is crucial for inflorescence head development and bract opening. No ethylene was detected in the inflorescences at the four developmental stages. However, a significant higher respiration rate was recorded at FB stage with actively developing and opening true flowers in the inflorescence. The high respiration rate eventually leads to depletion of soluble sugars and starch grains in involucral bracts and inflorescence peduncle, respectively. Thereafter, involucral bracts showed browning and senescing. This result implies that the inflorescence head is a major sink for photoassimilates during flowering stage. Thus, soluble sugars exhaustion is expected to be a main factor of inflorescence senescence.

Po2 measurements in the microcirculation using phosphorescence quenching microscopy at high magnification

In phosphorescence quenching microscopy (PQM), the multiple excitation of a reference volume produces the integration of oxygen consumption artifacts caused by individual flashes. We analyzed the performance of two types of PQM instruments to explain reported data on Po2 in the microcirculation. The combination of a large excitation area (LEA) and high flash rate produces a large oxygen photoconsumption artifact manifested differently in stationary and flowing fluids. A LEA instrument strongly depresses Po2 in a motionless tissue, but less in flowing blood, creating an apparent transmural Po2 drop in arterioles. The proposed model explains the mechanisms responsible for producing apparent transmural and longitudinal Po2 gradients in arterioles, a Po2 rise in venules, a hypothetical high respiration rate in the arteriolar wall and mesenteric tissue, a low Po2 in lymphatic microvessels, and both low and uniform tissue Po2. This alternative explanation for reported paradoxical results of Po2 distribution in the microcirculation obviates the need to revise the dominant role of capillaries in oxygen transport to tissue. Finding a way to eliminate the photoconsumption artifact is crucial for accurate microscopic oxygen measurements in microvascular networks and tissue. The PQM technique that employs a small excitation area (SEA) together with a low flash rate was specially designed to avoid accumulated oxygen photoconsumption in flowing blood and lymph. The related scanning SEA instrument provides artifact-free Po2 measurements in stationary tissue and motionless fluids. Thus the SEA technique significantly improves the accuracy of microscopic Po2 measurements in the microcirculation using the PQM.

Ethylene Biosynthesis and Fruit Color Development in `Pink Lady' Apples during Growth and Maturation

Growth and maturation of `Pink Lady' (Malus domestica Borkh.) apples with special emphasis on ethylene biosynthesis and color development were monitored in Western Australia during 2002-2003. Changes in fruit growth, respiration rate, ethylene production, anthocyanin accumulation and development of red blush were evaluated between 60 days after full bloom (DAFB) and commercial harvest (191DAFB). Fruit diameter, length and fresh weight showed the typical single sigmoid growth curve, with linear increases until 158 DAFB. High respiration rate and ethylene production were recorded 60 DAFB followed by rapid decrease until 144 DAFB and then a steady increase, which peaked between 172 and 179 DAFB. Red blush on the fruit surface showed steady increase from 167 DAFB and corresponded to concomitant decrease in hue angle. Total anthocyanin increased from 167 DAFB till harvest and synchronized with increasing ethylene and maturity of apples. There were significant (P ≤ 0.001), direct linear relationships between ethylene production and total anthocyanin (r = 0.63, y = 7.6032x + 2.4756), total anthocyanin and red blush (r = 0.74, y = 0.5082x -1.54). Significant (P ≤ 0.001) negative direct linear relationships between total anthocyanin and hue angle (r = -0.89, y = -0.5973x + 110.14), and ethylene and hue angle (r = -0.69, y = -5.37x + 109.60) were recorded. Increasing anthocyanin content and red blush also coincided with decreasing daily temperatures in the orchard. Reduction in fruit firmness and acidity and increase in TSS from 167DAFB were good indicators of advancing maturity of apples. Our experimental results indicate that red blush in `Pink Lady' apples develops a few weeks before harvest and is regulated by ethylene biosynthesis and temperature.