No abstract

In rice-consuming countries, specific varieties are recognized as premium, "gold standard" varieties, while others are recognized as being superior but second best, despite being identical using the current suite of tools to evaluate quality. The objectives of this study were to determine if there are distinguishable differences in sensory properties of premium and second best varieties and whether these differences are common to premium varieties. Color, an important sensory property, was determined on the raw and cooked rice using a colorimeter. As raw rice, some of the premium varieties were whiter than their second best counterparts while others were not. However, when cooked, with two exceptions, the premium varieties were of the same or greater whiteness than their counterparts. A trained sensory panel employed descriptive sensory analysis, an objective tool, to characterize and analytically measure the flavor (aromatics, taste, mouthfeel) and texture of premium and second best varieties collected from nine rice-consuming countries. Sweet taste, popcorn aroma/ flavor, and water-like metallic mouthfeel showed significant differences in intensity between the premium-second best variety pairs. Slickness, roughness, and springiness were the major traits that distinguished the texture of varieties. Quality evaluation programs do not routinely measure these texture and flavor traits, but the fact that they distinguished the varieties in most pairs indicates that their measurement should be added to the suite of grain quality tests in the development of new higher-yielding, stresstolerant varieties. The incorporation of premium quality will ensure that quality is no impediment to widespread adoption leading to enhanced productivity and food security.

: Maintaining flavor, aroma, microbial, and postharvest quality after processing and throughout the distribution chain is a major challenge facing the fresh‐cut fruit industry. Flavor and aroma are most often the true indicators of shelf‐life from the consumer's point of view. Changes in post‐cutting sensory attributes during freshcut storage at 4 °C in cantaloupe harvested at 4 distinct maturities (¼, frac12;, frac34;, and full slip) were subsequently investigated. Trained descriptive sensory panelists were used in a 2‐y study to assess sensory differences after 0, 2, 5, 7, 9, 12, and 14 d. A texture analyzer was also used in an attempt to verify textural properties revealed by the panelists. The V4‐slip harvested fruit were firmer than the other 3 maturities, and ¼‐slip cubes retained the most firmness through freshcut storage. Correspondingly, fruity and sweet aromatic flavor were significantly less intense in the ¼‐slip cubes compared with ½‐ and ¾‐slip maturities. Sweet taste was consistently significantly less intense in the ¼‐slip cubes than the other maturities during the entire storage period. Hardness was more intense (harder) in ¼‐slip cubes during 0 to 9 d. This trend was almost identical in the instrumental texture determinations for the force and slope at the 1st bioyield point of the force deformation curves. Meanwhile, ¼‐slip cubes were significantly less intense than the other maturities in surface wetness and moisture release on day 0 and throughout storage. It appears that fresh‐cut cantaloupe cubes with desirable sensorial attributes can be prepared with fruit when harvested ½ slip but not from ¼‐slip fruit.

Seedless triploid watermelons have increased in popularity since the early 1990s, and the demand for seedless fruit is on the rise. Sweetness and sugars are crucial breeding focuses for fruit quality. Volatiles also play an important role; yet, we found no literature for seedless varieties and no reports using solid-phase microextraction (SPME) in watermelon. The objective of this experiment was to identify volatile and semivolatile compounds in five seedless watermelon varieties using carboxen divinylbenzene polydimethylsiloxane solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS). Fully ripe watermelon was squeezed through miracloth to produce rapid juice extracts for immediate headspace SPME GC-MS. Aldehydes, alcohols, ketones, and one furan (2-pentyl furan, a lipid oxidation product) were recovered. On the basis of total ion count peak area, the most abundant compounds in five varieties were 3-nonen-1-ol/(E,Z)-2,6-nonadienal (16.5-28.2%), (E)-2-nonenal (10.6-22.5%), and (Z)-6-nonenal (2.0-11.3%). Hexanal was most abundant (37.7%) in one variety (Petite Perfection) [corrected] The most abundant ketone was 6-methyl-5-hepten-2-one (2.7-7.7%). Some sensory attributes reported for these compounds are melon, citrus, cucumber, orange, rose, floral, guava, violet, vegetable, green, grassy, herbaceous, pungent, fatty, sweet, and waxy. Identifying and relating these compounds to sensory attributes will allow for future monitoring of the critical flavor compounds in seedless watermelon after processing and throughout fresh-cut storage.

No abstract

Voltage-gated calcium (Ca2+) channels contribute to impulse propagation in excitable cells and also regulate intracellular levels of Ca2+. High voltage-activated (HVA) Ca2+ channels are heteromultimeric membrane proteins. The pore-forming, voltage-sensing subunit is the alpha1 subunit. We have cloned 3 HVA Ca2+ channel alpha1 subunit cDNAs from Schistosoma mansoni. One of these sequences most closely resembles the L-type class of HVA alpha1 subunits. The other two sequences are most closely related to non L-type alpha1 subunits. These schistosome alpha1 subunits have many of the features common to HVA Ca2+ channels, but also have distinct structural motifs. Analysis of the structural and functional properties of schistosome Ca2+ channel subunits may provide information about these critical components of excitable cells.

Cantaloupe (Cucumis melo L. var. reticulatus Naudin) were evaluated during development and then fresh-cut cubes were stored after preparation from various maturities to track quality changes during storage. Flowers were anthesis tagged one morning in two seasons (years) and developing fruit were harvested weekly at 13, 20, 27 to 28, and 34 to 35 days after anthesis (DAA). Mature fruit were harvested at 37 to 38 DAA with five distinct maturities: 1/4-, 1/2-, 3/4-slip, full-slip (FS), and overripe (OR). Hunter L* and a* color values indicated a change from pale green to light orange that occurred 28 DAA. There were significant decreases in L*, a*, and b* by day 9 in storage (4 °C) as fresh-cut cubes. After 28 DAA, sucrose dramatically increased, and this was positively correlated with increases in both total sugars (r = 0.882, P = 0.084) and percent soluble solids concentration (r = 0.939, P = 0.041). Gradual deterioration occurred during storage, as determined by a uniform subjective quality criterion, which was independent of maturity. There was a negative linear trend in hand-held and instrumental firmness over the length of storage for each maturity level, and the slopes decreased significantly with increasing maturity, indicating the effect of storage duration decreased as harvest maturity increased. There was a significant increasing trend in vitamin C (P = 0.042) during development from 12 through 35 DAA, then losses were greater in fresh-cut cubes prepared from full-slip fruit (65%) than less-mature fruit: 3/4-slip, 50%; 1/2-slip, 48%; 1/4-slip, 40%. The pH of mesocarp tissue dropped to the lowest value (5.25) just before physiological maturity at 27 to 28 DAA, then peaked after harvest (6.51–6.79), and declined somewhat by the end of storage as fresh-cut cubes. In sum, muskmelon fruit used to produce fresh-cut cubes should be harvested ≥1/2-slip to attain optimum physiological quality and consumer acceptability.

The distribution of nitric oxide synthase (NOS) immunoreactivity and putative NOS activity in adult Schistosoma mansoni was analysed using 3 different types of NOS antibodies and NADPH-diaphorase histochemistry. Although potential involvement of the gaseous radical nitric oxide (NO) in host response to infection by schistosomes has been suggested, there is little or no information available regarding the role, or even the presence, of the NO pathway in schistosomes themselves. Here, we demonstrate that antibodies against neuronal NOS (nNOS) and inducible NOS (iNOS) isoforms stain adult worms with distinctive patterns; anti-endothelial NOS (eNOS) shows no selective labelling. nNOS-like immunoreactivity is found in the main nerve cords and the peripheral nervous system. Putative sensory neurons with apical neuronal processes leading to the tegument of male worms are also immunoreactive for nNOS. Anti-iNOS labels a variety of predominantly non-neuronal tissues, showing intense labelling at or near the surface of the worm and in components of the gastrointestinal tract. The distribution of NADPH-diaphorase reactivity (a histochemical marker of NOS), is generally similar to the pattern of NOS immunoreactivity, including labelling of neuronal-like cells as well as developing eggs. These results suggest that an NOS-like enzyme is present in S. mansoni, and indicate potential roles for the different NOS isoforms in neuronal signalling, reproduction and development.