S. Paul Singh

Preharvest bagging with wavelength‐selective materials enhances development and quality of mango (Mangifera indica L.) cv. Nam Dok Mai #4

BACKGROUND Preharvest bagging has been shown to improve development and quality of fruits. Different light transmittance bags showed different effects on fruit quality. This study presents the benefits of using newly developed plastic bagging materials with different wavelength-selective characteristics for mangoes (cv. Nam Dok Mai #4). Mangoes were bagged at 45 days after full bloom (DAFB) and randomly harvested at 65, 75, 85, 95, and 105 DAFB. The bags were removed on the harvest days. The wavelength-selective bags (no pigment, yellow, red, blue/violet, blue) were compared with the Kraft paper bag with black paper liner, which is currently used commercially for several fruits, and with non-bagging as a control. RESULTS Bagging significantly (p⩽0.05) reduced diseases and blemishes. Mango weight at 95 DAFB was increased approximately 15% by VM and V plastic bagging, as compared to paper bagging and control. Plastic bagging accelerated mango ripening as well as growth. Plastic-bagged mangoes reached maturity stage at 95 DAFB, while non-bagged mangoes reached maturity stage at 105 DAFB. Paper bagging resulted in a pale-yellow peel beginning at 65 DAFB, while plastic bagging improved peel glossiness. CONCLUSION Preharvest bagging with different wavelength-selective materials affected mango development and quality. Bagging mangoes with VM and V materials could reduce peel defects and diseases, increase weight, size, and sphericity, improve peel appearance, and shorten the development periods of mangoes. The results suggest a favorable practice using the newly developed VM and V plastic bags in the production of mangoes, and possibly other fruits as well.

Testing and Evaluation of Quality Changes of Treated Fresh-Cut Tropical Fruits Packaged in Thermoformed Plastic Containers

Fresh-cut fruit accounted for nearly

Vibration induced settling of a sphere in a Herschel-Bulkley fluid

300 at retail in the U.S. in 2004, with projected sales ranging between

Postharvest Damage of Mangosteen and Quality Grading Using Mechanical and Optical Properties as Indicators

1 and

Damage Reduction to Food Products During Transportation and Handling

2 billion by 2008. The choice of packaging materials and the atmospheric conditions both inside and outside the package contribute significantly to the shelf-life of these products. This study evaluated quality changes such as firmness, color, total soluble solids (TSS), titratable acidity (TA), sensory quality, and microbial safety of fresh-cut mangoes, pineapples, melons, and mixes of these fruits. Chemical treatments to reduce browning, firmness loss, and decay for these fruits were also investigated. The most effective treatments for fresh-cut mangoes, pineapples, and melons were 0.1 M ascorbic acid, 0.2 M ascorbic acid, and 0.2 M ascorbic acid plus 0.2 M calcium chloride, respectively. These fresh-cut tropical fruits were packaged in three semi-rigid containers made of polyethylene terephthalate (PET), oriented polystyrene (OPS), and oriented poly(lactide) (OPLA). Gas composition in the package headspace and the time to reach steady-state conditions were observed to vary among fresh-cut packaging systems and affected their quality and shelf-life. The effects of package permeability, with regards to O2 and CO2, on quality and shelf-life of the fresh-cut products are discussed in this paper. Extended shelf-life was observed in fresh-cut mangoes, pineapples, and mixes packaged in PET due to reduced O2 and elevated CO2 atmosphere. Modified atmosphere of 6% O2 and 14% CO2 achieved in PET extended the shelf-life of fresh-cut pineapples from 6 to 13 days. The results suggest that shelf-life of fresh-cut fruit could be extended using appropriate semi-rigid containers.

Measurement and Analysis of Vibration Levels in Commercial Truck Shipments in Thailand and Its Impact on Packaged Produce

Abstract Settling of spheres suspended in a Herschel-Bulkley fluid with a yield stress under the influence of vibrations is of great practical significance while transporting liquid food systems such as soups, sauces and jams. A dimensionless equation has been developed to predict the settling time of a sphere in a Herschel-Bulkley fluid subjected to sinusoidal vibration. The model was used to determine the effect of random vibrations as induced in a shipping environment. A separation criterion has been developed to determine whether a particle will settle. Methods described in this paper can also be used to characterize non-Newtonian fluids.

The Relevance of Drop Tester Accuracy

Postharvest damage in fresh mangosteens at wholesale level in Thailand was investigated from April to October 2004. A total of 37.1% of the production yield was rendered inedible by damage during this period; damages included fruit cracking, hardened rinds, rough surfaces, translucent flesh, gummosis and decay. This study focused on a method of predicting damage based on the color of the skin of the affected mangosteen. As a first step, diameter, height, weight, and volume of large, medium, small, and undersize mangosteens were measured. The term, dimension ratio, was introduced as a sizing parameter identifying conventional trade size. The coefficient of static friction of the glossy- and rough-surface mangosteens on plexiglass, plywood, and galvanized steel sheet varied from 0.31 to 0.46. The color of sound and defective fruits was measured in terms of their tristimulus values X, Y, and Z. The corresponding chromaticity coordinates of a mangosteen, x and z, depended on the maturity stage of the fruit while y depended on the type of fruit surface. A ratio was proposed to test the accuracy of predicting internal defects from the color variation between two spots on the surface of the same fruit. The highest percentage of correct prediction was 67.4% with a color ratio of X1 (pink blush color on yellow ground color) to X2 (pink color) that was greater than 1.25.

Effect of Vibration as a Cause of Leakage in Aluminum Beer Cans in Palletized Loads

This chapter provides an insight to the role of packaging in providing protection to food products during transportation and handling. With increasing global demand for food products, producers of high quality fresh produce ship packaged produce across continents and oceans daily. Transportation and handling impart stresses from shocks, vibrations and compression forces that can produce bruising and accelerate ripening. The shelf life at retail is therefore critical, and requires protection to the food products after harvesting and packaging. Packages also provide food safety and enhance traceability and tracking through the entire value chain. Various packaging technologies that enhance the shelf life and insure the quality and freshness attributes are discussed.

Mechanical and Light Properties of Mangosteen Fruit as Related to Postharvest Quality

The purpose of this study was to measure and analyze the vibration levels in commercial truck shipments in Thailand. Trucks with leaf spring suspensions are the most common logistics method to move products in South East Asia. This study measured the vibration levels in two of the most commonly used truck types used to ship packaged goods as a function of road condition and vehicle speed. The data presented in this study will assist product and package designers to reduce damage in transit by using the recommended vibration test spectrums to evaluate products and packages prior to shipment. The data can also be used by test development organizations as part of lab-simulated methods to perform preshipment tests on packaged goods. The test shipments in this study consisted of packaged tangerine fruit from orchards to retailers. The results showed that an increase in truck speed resulted in an increase in vibration levels and damage to packaged fruit. The laterite (unpaved gravel surface) road condition produced the highest vibration level for a given truck and traveling speed followed by concrete highway and asphalt road conditions. Fruit damage was found to be greatest in the uppermost container for every combination of road, truck type, and traveling speed, which also corresponded to the highest vibration levels recorded. Results of damage in packaged tangerine fruit as a function of location in the payload is also presented.

Comparison of international mail trays

ASTM D 5276-98 “Standard Test Method for Drop Test of Loaded Containers by Free Fall,” [1] was written as the general test specification for permitting free-fall drop tests for packaged products. One of the fundamental characteristics for drop testers used to perform ASTM D 5276 is that they must produce a flat drop with tolerance limit set at ±2 deg. For drops other than flat drops, such as edges and corners, tolerance limits of ±5 deg have been specified. Although most drop testers are calibrated during manufacturing, they are often not checked for accuracy at their lab locations. This is primarily due to the lack of a calibration standard. This paper investigates the importance of drop test accuracy and reports observations, measurements, and documentation of changes in acceleration and velocity change measured on a test specimen as it is subjected to drops with increasing deviation from the desired impact orientation. A statistical analysis of accelerations as impact orientations deviated is provided and statistical trends in the data as impact angles change are reported. The results suggested that the existing tolerances for performing drops within ±2 deg as recommended by ASTM D 5276 are acceptable for flat drops and the tolerances for performing edge and corner drops within ±5 deg are not acceptable as they can result in larger deviations as the offset is increased beyond ±2 deg.