SOLAR TUNNEL DRYING OF TURMERIC (CURCUMA LONGA LINN. SYN. C. DOMESTICA VAL.) FOR QUALITY IMPROVEMENT

Turmeric is one of the most ancient medicinal spices of the world. As its homeland, India acts as the largest producer, exporter and consumer of turmeric. The value of turmeric is due to its color and flavor, which is being given by curcumin, volatile oil and oleoresin. The end quality of turmeric is very much dependent on its post-harvest methods. Traditionally, open sun drying is the chief method adopted for processing. In the present investigation, freshly harvested turmeric rhizomes were collected from 30 stations and drying experiments were conducted by adopting three methods: (1) solar tunnel drying; (2) conventional drying; and (3) commercial drying. Various pre-drying and post-drying treatments were conducted. The results proved that conventional processing could maintain the intrinsic quality up to a certain level, but extrinsic quality could not be achieved. Solar tunnel drying method is an effective alternative to traditional open sun drying, where retention of curcumin, volatile oil and oleoresin was high, with less drying time. The study also disclosed the importance of pre-drying and post-drying treatments and hygienic practices to be adopted during processing.

PRACTICAL APPLICATIONS

Solar tunnel dryer can be used to process most of the spices, vegetables, fruits and other perishable crops with maximum retention of intrinsic quality and for better shelf life. Substantial reduction of drying time and physical quality improvement with regard to international quality standards are the other advantages.     

Development of Food Ingredients from Navy Beans (Phaseolus vulgaris) by Roasting, Pin Milling, and Air Classification

Eight Navy bean samples, roasted between 92 and 125°C in a particle-to-particle heat exchanger, were ground to produce whole bean and hull flours. Dehulled bean flours were also separated into high protein (HPF) and high-starch fractions (HSF) by air classification. Whole bean flours contained 1.92% fat and 25.8% protein on the average. Hull flours contained between 31.2 and 50.2% dietary fiber, of which approximately 60% was crude fiber. Dehulled bean flour containing 26.8% protein was fractionated into HSF and HPF with average protein contents of 15.6 and 43.1%, respectively. Greater protein shift may be further accomplished by finer grinding and adjustment of the cut point. Residual trypsin inhibitor activity of HPF s ranged from 25–108 TIA/mg protein, down from 116 units in the raw control HPF. Hemagglutinins were inactivated from 110 HA units/mg to values ranging from 2.4–105 HA units/mg.     

MODELING THE EFFECT OF MICROSTRUCTURE ON FOOD EXTRACTION

Several cases of extraction of food components were analyzed applying the diffusion theory and Fick's second law to different microstructural architectures. A mathematical algorithm was developed for a two‐dimensional heterogeneous system and programmed in MATLAB. Architectures examined include: (1) structure with straight pores, (2) flake with impermeable platelets, (3) matrix with impermeable dispersed particles and, (4) cellular material. Results show that the architecture of phases in the solid matrix is more important than parameters normally used to correct the diffusivity for structural effects (tortuosity, porosity, volume fraction, etc.). Simulated extraction curves were similar to those obtained from experimental data where an empirical effective diffusivity was calculated. These results suggest a more fundamental approach to modeling of extraction in foodstuffs based on the microstructure and local architecture.     

A RESEARCH NOTE: SENSORY QUALITY CHANGES OF HIGH MOISTURE PINEAPPLE BITS DURING STORAGE

Minimally processed high moisture pineapple bits prepared in sucrose syrups, in order to decrease water activity to 0.92, 0.95 and 0.97, were stored at 30, 35 and 40C and evaluated by selected and trained sensory panelists using the Karlsrühe Quality Test. Color, flavor and texture changes were significantly lower for the 0.92 a_w product stored at 30C. It can be predicted by shelf‐life estimation that this product will maintain a satisfactory sensorial and microbiological quality for up to 50 days.     

A Planning Model for the Fuerte-Carrizo Irrigation System, Mexico

A methodology is presented for planning the operation of the Fuerte-Carrizo irrigation system in northwest Mexico. The system has two storage dams, two irrigation districts, and water transfer capabilities between both dams. The methodology uses a combination of linear programming (LP) and simulation. The LP model maximizes the net return of the farmers, subject to restrictions of the system, availability of water and land, and water transfer relationships. The simulation model is programmed as a microcomputer interactive package simulating the performance of the system. The methodology has proven to be a useful tool to assist those responsible for the operation of the irrigation system.     

ULTRASTRUCTURE OF SOY PROTEIN FIBERS FRACTURED BY VARIOUS TEXTURE MEASURING DEVICES

Abstract. Spun soy fibers fractured by the tensile test, Warner-Bratzler shear, Kramer Shear Press and a modified Volodkevich wedge were examined with the scanning electron microscope. Fracture in the tensile test occurred almost always at a macrocavity, the weakest point in the fiber. Warner-Bratzler shear induced compression and flow at the zone of rupture, but not as markedly as in the case of the modified Volodkevich wedge. Fracture by the Kramer Shear Press was the closest to pure shear. Some of the exposed fracture surfaces revealed internal structures in the fibers such as macrocavities and distinct skin and core sections. The mechanism of rupture by these tests was more complex than expected.