Four formulas were prepared for produetion of low phenylalanine Egyptian shamy bread suitable for phenylketonuria (PKU) patients. The formulas were based on partial replaeement of first break wheat flour (low protein flour) with different levels of eom stareh. Peetin and earboxymethyleellulose (CMC) were used as a texture modifier and to improve staling rate of bread. Shamy bread made of 100% first break wheat flour was also prepared for eomparison. Chemieal eomposition, amino aeids eontent, dough eharaeteristies, baking test, sensory evaluation and staling rate of bread were investigated. A remarkable reduetion of protein, eonsequently, phenylalanine of bread was deteeted. Phenylalanine eontent of formula "D", whieh eontained 66 g of eom stareh, 30 g of first break wheat flour, 2 g of peetin and 2 g of CMC, was redueed by 62% eompared with the eontrol. The rheologieal properties of the dough were affeeted by stareh and hydroeolloids ineorporation. Sensory eharaeteristies of bread indieated that all formulas were aeeeptable, but formula "D" seems to be superior for PKU patients.

FIG. 2. The permittivity e 0 and dielectric loss e 00 of EPDM composites (a) CGM and (b) CF.

The effect of different thermal and chemical pre-treatments on quality and enzyme activities of smoked mushroom was investigated. Mushrooms were blanched (water and steam) and dipped in different concentrations of SO 2 , H 2 O 2 , ethylenediaminetetraacetic acid (EDTA) and citric acid for 10 min before smoking. Enzyme activities, colour characteristics, microbiological and sensory examinations were carried out every 2 weeks up to 8 weeks of storage at 4°C. Smoked mushroom pre-treated with sulphites (SO 2 ), H 2 O 2 and steam blanching had the best colour values, better scores for all sensory characteristics and lower non-enzymatic browning compared with the other pre-treatments. Pre-treatment against total aerobic bacteria, yeast and moulds was the most effective when using citric acid, EDTA and steam, followed by smoking of mushroom. The most effective pre-treatments on quality and safety of smoked mushrooms were those using H 2 O 2 and steam. It can be concluded that thermal and chemical treatments followed by smoking of mushroom reduce enzyme activities and are suitable for preserving mushrooms.

RESUMENEstudio comparativo entre la destiidratación convencional y en microonda del kimbombó.Este estudio se ha realizado para evaluar los diferentes pretratamientos y métodos de deshidratación en la calidad del kimboníibó. No se encontraron diferencias significativas entre ellos respecto a la composición química de las muestras de kimbombó deshidratadas. La inmersión en solución de metabisulf ito sódico al 0.1 % a temperatura ambiente y la inmersión en solución de metabisulf ito sódico al 0.1 % a 92-95 °C mejoraron la retención de ácido ascórbico de las muestras de kimbombó después de la deshidratación tanto utilizando el homo convencional como el homo microonda. Además el menor tiempo necesario para la deshidratación usando el horno microondas produjo menos destrucción de ácido ascórbico. La mayor relación de rehidratación fue encontrada en muestras de kimbombó no tratadas o deshidratadas usando horno microondas tras inmersión en metabisulf ito sódico al 0.1 % y 92-95 °C. Las muestras de kimbombó deshidratadas por secado al sol y homo convencional tuvieron menores porcentajes de retención de clorofilas totales y carotenoides que las de muestras de kimbombó deshidratadas usando homo microondas. La apariencia general y la calidad del color de las muestras de kimbombó deshidratadas mediante horno microondas fueron significativamente diferentes de aquéllas deshidratadas mediante homo convencional o secadas al sol. PALABRAS-CLAVE: Carotenoide SUMMARY Comparative study between microwave and conventional dehydration of okra.This study was conducted to evaluate different pre-treatments and dehydration methods on the quality of okra. No significant differences were found among pretreatments and dehydration methods for the chemical composition of dehydrated okra samples. Dipping in 0.1 % sodium metabisulphite solution at room temperature and immersion in 0.1 % sodium metabisulphite solution at 92-95 °C improved the retention of ascorbic acid of okra samples after dehydration by either conventional or microwave oven. Also, the reduced dehydration time required for microwave dehydration produced far less destruction of ascorbic acid. The highest rehydration ratio was found in unwashed okra sample and dehydrated by moowave after immersion in 0.1 % sodium metabisulphite solution at 92-95 °C. Dehydrated okra samples by sun drying and conventional oven had lower retention percentages of total chlorophyll and carotenoids than those of dehydrated okra samples by microwave oven. The general appearance and colour scores of dehydrated okra samples by microwave were significantiy different from those of conventionally dehydrated or sun dried okra samples.

Okara (the residue of soymilk manufacturing) was used as a protein source in the preparation of pan bread. Okara was dried at low-temperature (40-50°C) in a forced air drying oven, milled to obtain okara flour (OF) and blended with wheat flour 72% extraction at the 10, 20,30 and 40% replacement levels. The influence of this replacement on the rheological properties of dough, chemical, baking, organoleptic properties of bread was investigated. Breads were stored at room temperature for 5days and staling rate was also studied. Results showed that water absorption, dough development time and stability increased, while mixing tolerance index and dough weakening decreased by increasing the level of replacement. Extensibility and dough energy decreased but resistance to extension and the proportional number increased by increasing the level of okara flour. Protein content of bread increased by increasing the level of replacement. Maximum improvement of protein achieved was about 57% by using 40% OF. Loaf weight increased, while loaf volume and specific loaf volume decreased by increasing the level of OF. Clear reduction of bread staling rate caused by okara flour addition. Baking quality and organoleptic evaluation showed that OF can be used to supplement wheat flour in making of pan bread up to 30% replacement level.