Guayule (Parthenium argentatum A. Gray), a Renewable Resource for Natural Polyisoprene and Resin: Composition, Processes and Applications.

Natural rubber is an essential material, especially for plane and truck tyres but also for medical gloves. Asia ranks first in the production of natural rubber, of which the Hevea tree is currently the sole source. However, it is anticipated that this source alone will not be able to fulfill the growing demand. Guayule, a shrub native to northern Mexico and southern United States, may also contribute. This plant not only contains polyisoprene, but also resin, a mixture of lipids and terpenoids. This review summarizes various aspects of this plant, from the usage history, botanical description, geographical distribution and cultivation practices, down to polyisoprene and resin biosynthesis including their distribution within the plant and molecular composition. Finally, the main processes yielding dry rubber or latex are depicted, as well as the properties of the various extracts along with economic considerations. The aim is to provide a wide picture of current knowledge available about this promising crop, a good feedstock candidate for a multiple-product biorefinery.

Feasibility and use of vitamin A-fortified vegetable oils among consumers of different socioeconomic status in Thailand.

BACKGROUND: Vitamin A losses infortified vegetable oils can differ, depending upon the cooking and distribution conditions of a country. OBJECTIVE: To determine vitamin A losses in different vegetable oils during transportation, cooking, and storage among consumets of different socioeconomic status. METHODS: Soybean, rice bran, and palm oils were fortified with vitamin A palmitate at 267 microg/15 mL. The oils were packaged in 5-L metal cans and 250-mL polyethylene terephthalate (PET) bottles and then stored under light and dark conditions. Unopened and opened bottles were stored for 13 and 4 weeks, respectively. Fortified palm oil also was bulk transported in trucks and packaged in 1-kg polypropylene bags that were closed with rubber bands. Vitamin losses were measured after cooking at 120 degrees and 170 degrees C for 5 and 10 minutes in iron, aluminum, Teflon, and glass pans. RESULTS: Vitamin A losses of oils in PET bottles stored under light conditions were 20% to 25% at the 5th week and became greater than 80% after 13 weeks, whereas losses under dark conditions and in metal containers were less than 15%. Loss during bulk transportation was 25%, with no change in peroxide value. Losses in opened bottles after 4 weeks under light conditions were 50% to 90% based on the degree of oil unsaturation; however, losses under dark conditions were less than 5%. Losses after cooking at 120 degrees and 170 degrees C for 10 minutes were less than 5% and 15%, respectively. The type of pan did not affect the amount of loss. The peroxide values of oils in bottles increased during storage under light conditions. CONCLUSIONS: Fortification of vegetable oils with vitamin A for consumers of different socioeconomic status is feasible; however, light protection is needed for better stability.