A study of chlorophyll-like and phycobilin pigments in the C endosymbiont of the apple- snail <i>Pomacea canaliculata</i>

Pigments present in the brown-greenish C morph of an intracellular endosymbiont of Pomacea canaliculata were investigated. Acetone extracts of the endosymbiotic corpuscles showed an absorption spectrum similar to that of chlorophylls. Three fractions obtained from silica gel column chromatography of the acetone extracts (C_I , C_II and C_III ), were studied by positive ion fast atom bombardment-mass spectrometry (FAB–MS) and hydrogen-nuclear magnetic resonance (H-NMR). Results indicated the presence of (1) a sterol in the yellow colored C_I fraction; (2) a mixture of pheophorbides a and b in the major green fraction, C_II; and (3) a modified pheophorbide a in the smaller green fraction, C_III . Aqueous extracts of the C endosymbiont did not show evidence of the occurrence of C-phycocyanin, allophycocyanin or phycoerithrin (light absorption, fluorescence emission, and electrophoresis of the protein moieties) while cyanobacterial cells (Nostoc sp.) showed evidence of C-phycocyanin and allophycocyanin. The possible phylogenetic and functional significance of the pigments present in the C endosymbiont is discussed.     

Decolorization of β-Carotene in Model Systems Simulating Dehydrated Foods. Mechanism and Kinetic Principles

The mechanism and kinetic principles of β-carotene decolorization under reduced oxygen (0–20.9%) low water activity (“dry”– 0.84) and 35°C were investigated in a model system. Oxygen was found to be a crucial factor in β-carotene degradation. Rate of decolorization due to oxygen was found to be influenced by the amount of oxygen adsorbed. This amount was influenced by oxygen partial pressure and the physical and chemical structure of the adsorbent. β-Carotene decolorization was found to be strongly affected by the presence of free radical initiators. On the other hand, degradation was slowed down when an antioxidant was added. β-Carotene retention curves were sigmoidal with three regions, namely, an induction period, a fast “main” period, and a retardation period-typical of an autocatalytic radical reaction. Water activity was found to play a protective role in β-carotene decolorization.     

EFFECT OF HEAT TREATMENT ON THE QUALITY OF COOKED CARROTS

We investigated the effect of heat treatment on the quality of cooked carrots (texture, chemical, and sensory evaluation). Slices of three carrot varieties (Rubika, Kundulus, and Rothild) were cooked at 90–120°C for 2–70 min. Compressive failure stress and rupture work were a by a Zwick Universal Testing Machine. Textural softening could be expressed by an exponential equation of the type: S = A exp(-kt), where 6 = rupture stress, t = cooking time, and A and k are constants. Plotting k versus l/T (T = cooking temperature, °K) revealed an Arrhenius-type relationship with apparent activation energy of about 28, 27, and 22 Kcal/mole for Rubika, Rothild, and Kundulus varieties, respectively. Chemical analysis (dry matter and p-carotene) showed that the cooking process caused insignificant changes. Statistical analysis of the sensory assessments showed an overall significant preference for 3 mm slice thickness and 110°C cooking temperature.     

RELATION BETWEEN ETHNIC ORIGIN AND GSR REACTIVITY IN PSYCHOPHYSIOLOGICAL DETECTION.

ANALYZED PSYCHOPHYSIOLOGICAL DATA OF 3 JEWISH AND 1 BEDOUIN SAMPLES IN CONNECTION WITH THE DETECTABILITY OF A PREVIOUSLY CHOSEN CARD. SS OF NEAR EASTERN ORIGIN TENDED TO SHOW LOWER PULSE RATE, HIGHER BASIC SKIN CONDUCTANCE, AND LOWER RELEVANT GSR REACTIVITY. IT IS PROPOSED THAT PSYCHOCULTURAL DIFFERENCES MIGHT EXPLAIN THE CONSISTENT DIFFERENTIAL GSR REACTIVITY TO THE RELEVANT STIMULI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

STORAGE STABILITY OF DEHYDRATED FOOD EVALUATION OF LITERATURE DATA

Literature data on storage stability of dehydrated foods were compiled and critically evaluated. Stability of nine different groups of dehydrated products is reported in terms of time required to produce earliest quality defects, and in terms of specific quality measurements at time of failure, where these were available. Methods of drying, storage and pretreatment are also reported for each product. The paper also discusses the contribution of various factors to stability of dehydrated foods, as well as research needs in this area.     

FORMATION OF RESISTANT STARCH DURING DEEP-FAT FRYING AND ITS ROLE IN MODIFYING MECHANICAL PROPERTIES OF FRIED PATTIES CONTAINING CORN, RICE, WHEAT, OR POTATO STARCH AND WATER

Resistant starch (RS) was determined in patties (5.1 cm diameter, 1.27 cm high) prepared by mixing starch (corn, rice, wheat, or potato) in distilled water and immersion fried in canola oil (at 170 ± 3C). The RS content (expressed as % of total starch) in corn starch increased from 4.25 to 5.43% (±0.11) in the core region of a patty, whereas in the outer crust region the RS level was constant throughout the frying process. Similar trend was observed in potato, rice, and wheat starch patties. Upon varying the amylose content in the corn starch from 21 to 70%, the initial RS content (prior to frying) increased from 3.47 to 22.74 (±0.11%), following a linear relationship. Maximum force (MF) to puncture the crust of each starch patty was determined for frying duration of 3 to 15 min. Patties exhibiting higher RS content prior to frying, developed crusts with higher MF to puncture the crust, exhibiting a linear relationship between those two variables.     

Gel-strength in Restructured Potato Products Affects Oil Uptake during Deep-fat frying

A controllable food system consisting of a restructured potato product was employed to study the effect of gel-strength on oil uptake. Water loss and oil uptake were affected markedly by gel-strength. Oil uptake decreased as gel-strength increased. The oil uptake ratio, U_R′ (weight ratio of the oil uptake to the water evaporated during frying) was utilized to assess the effectiveness of reducing oil absorption during frying. This criterion was useful for comparison of restructured potato products with different initial or final moisture contents.