Extension of the shelf-life of fresh oyster mushrooms (Pleurotus ostreatus) by modified atmosphere packaging with chemical treatments

The objective of this study was to improve the preservation of fresh oyster mushrooms by modified atmosphere packaging (MAP) and chemical treatments. The MAP effects and treatments on organoleptic quality, weight loss, cell permeability, texture changes and polyphenol oxidase (PPO) activity were studied. In addition, three packaging materials were used for MAP mushroom storage. Low-density polyethylene (LDPE) proved to be a more suitable material than polyvinyl chloride (PVC) and LDPE-PVC as MAP materials. On the other hand, for mushrooms storage, MAP in combination with chemical treatments (sorbitol 0.05 g/100 g, CaCl2 1.0 g/100 g and citric acid 3.0 g/100 g) showed inhibitory effects on weight loss and mushrooms cell permeability. Furthermore, the results of polyphenol oxidase (PPO) activity, texture and organoleptic analysis also showed that active MAP, composed of 1.5% O2 and 20% CO2 and combined with chemical treatments, was found to be beneficial in maintaining oyster mushrooms quality and shelf-life.Key words: Modified atmosphere packaging (MAP), oyster mushroom, shelf-life, preservation, chemical treatments

Plowing for Rover Control on Extreme Slopes

Abstract Planetary rovers are increasingly challenged to negotiate extreme terrain. Early destinations have been benign to preclude risk, but canyons, funnels, and newly discovered holes present steep slopes that defy tractive descent. Steep craters and holes with unconsolidated material pose a particularly treacherous danger to modern rovers. This research explores robotic braking by plowing, a novel method for decreasing slip and improving mobility while driving on steep unconsolidated slopes. This technique exploits subsurface strength that is under, not on, weak soil. Starting with experimental work on Icebreaker, a tracked rover, and concluding with detailed plow testing in a wheel test-bed the plow is developed for use. This work explores using plows of different diameters and at different depths as well as the associated braking force. By plowing the Icebreaker rover can successfully move on a slope with a high degree of accuracy thereby enabling science targets on slopes and crater walls to now be considered accessible.