Rheological characteristics of suwari and kamaboko gels made of surimi from Indian major carps

The gel strength, compressibility and folding characteristic of suwari (set) and kamaboko (set and cooked) gels prepared from rohu ( Labeo rohita ), catla ( Catla catla ) and mrigal ( Cirrhinus mrigala ) surimi were examined to understand the occurrence of suwari and modori phenomena in surimi from major freshwater carps. Suwari setting of gels did not take place at lower temperatures. Suwari gels showed good gel strength at 50 °C for rohu and at 60 °C for catla and mrigal after 30 min setting time. Incubation for 60 min decreased the gel strength at 60 °C for rohu and catla. Setting at 25 °C followed by cooking at 90 °C increased the gel strength. Increased setting temperature, however, decreased the gel strength of cooked gels. Gel strength and compressibility data were supported by folding characteristics. © 2002 Society of Chemical Industry     

Comparison of personal, indoor, and outdoor exposures to hazardous air pollutants in three urban communities

Two-day average concentrations of 15 individual volatile organic compounds (VOCs) were measured concurrently in (a) ambient air in three urban neighborhoods, (b) air inside residences of participants, and (c) personal air near the breathing zone of 71 healthy, nonsmoking adults. The outdoor (O), indoor (I), and personal (P) samples were collected in the Minneapolis/St. Paul metropolitan area over three seasons (spring, summer, and fall) in 1999 using charcoal-based passive air samplers (3M model 3500 organic vapor monitors). A hierarchical, mixed-effects statistical model was used to estimate the mutually adjusted effects of monitor location, community, and season while accounting for within-subject and within-time-index (monitoring period) correlation. Outdoor VOC concentrations were relatively low compared to many other urban areas, and only minor seasonal differences were observed. A consistent pattern of P > I > O was observed across both communities and seasons for 13 of 15 individual VOCs (exceptions were carbon tetrachloride and chloroform). Results indicate that ambient VOC measurements at central monitoring sites can seriously underestimate actual exposures for urban residents, even when the outdoor measurements are taken in their own neighborhoods.     

Activation of platelets exposed to shear stress in the presence of smoke extracts of low-nicotine and zero-nicotine cigarettes: the protective effect of nicotine.

Mainstream and sidestream smoke extracts of both high-tar and low-tar cigarettes have been shown to increase platelet activation directly and to sensitize them to further activation by exposure to mechanical stimuli such as shear stress. However, nicotine has an inhibitory effect on platelet activation, opposite to that of whole cigarette smoke extracts. To distinguish between the nicotine-dependent and non-nicotine-dependent effects of smoke, platelets were exposed to mainstream and sidestream smoke extracts of low-nicotine and zero-nicotine cigarettes in vitro under flow conditions comparable with the normal circulation, and their activation state was measured using a modified prothrombinase-based assay. Both low-nicotine and zero-nicotine extracts caused increased platelet activation upon exposure to shear stress, and they caused significantly greater activation than extracts from ordinary high-tar, high-nicotine cigarettes. That nicotine was crucial was confirmed by adding 50 nM nicotine (comparable with the nicotine level in smokers' plasma) to zero-nicotine smoke extracts and demonstrating a reduction in the shear-dependent rate of platelet activation of more than 75%.     

Enhancing protein and sugar release from defatted soy flakes using ultrasound technology

This research focused on the use of high-power ultrasound prior to soy protein extraction to simultaneously enhance protein and sugar release in the extract. Defatted soy flakes dispersed in water were sonicated for 15, 30, 60 and 120 s using a bench-scale ultrasound unit. The ultrasonic amplitudes used were: 0, 21, 42, 63 and 84 μm_pp (peak-to-peak). The respective power densities were 0.30, 0.87, 1.53 and 2.56 W/ml. Scanning electron micrographs of sonicated samples showed the structural disruption of soy flakes. The particle size decreased nearly 10-fold following ultrasonic treatment at high amplitudes. Sonication at high amplitude for 120 s gave the highest increase in total sugar released (50%) and protein yield (46%) when compared with non-sonicated samples (control). Ultrasonic pretreatment was also carried out with and without cooling for temperature moderation. The heat generated during sonication had no significant effect on protein and sugar release from defatted soy flakes. The use of ultrasound can significantly improve protein yield and reduce the overall cost of producing soy protein from flakes.     

Sorption of Ethyl Butyrate and Octanal Constituents of Orange Essence by Polymeric Adsorbents

Sorption characteristics, rates and capacities of polymeric adsorbents (XAD-4, XAD-7, XAD-16, Duolite ES-865, Duolite S-761, Porapak-Q and XUS-43436) for ethyl butyrate and octanal were determined using model solutions. Sorption of these two principal components of aqueous orange essence, was evaluated utilizing the Freundlich isotherm model. Breakthrough curves were determined using XAD-16 as adsorbent. The capacity of XAD-16 for ethyl butyrate in the column system was 426±212 mg/g. There was no column breakthrough for octanal even after 130 bed volumes. Most (91.4%) of the adsorbed ethyl butyrate was eluted from XAD-16 resin by 95% ethanol elution. Recovery of adsorbed octanal from the resin was 66.4%.     

Evaluation of Time-Intensity Sensory Responses using a Personal Computer

A method is presented which utilizes a personal computer to measure time-intensity (T-I) sensory responses. The judge uses a game paddle which moves an “X” along a fixed scale appearing on the monitor screen to indicate the attribute intensity at each instant in time. A clicker device on the game paddle can be used to record the occurrence of events such as initial mouth entry and time of swallowing. Data acquisition is continuous with the data stored on discs. This technique has advantages over strip chart recorder methods. Disc storage allows rapid and efficient data analysis. Judges can perform the evaluations virtually unsupervised with only minimal training.     

Lack of Vitamin B6 Activity of 6-Hydroxypyridoxine

Hydroxylation of the C-6 position of pyridoxine has been described recently as a mechanism for the degradation of vitamin B6 in foods. The nutritional properties of the resulting 6-hydroxypyridoxine in mammals have not been previously evaluated. 6-Hydroxypyridoxine was synthesized and its structure confirmed by UV and NMR spectroscopy. A rat bioassay with multiple dose levels was conducted to compare the vitamin B6 activity of pyridoxine and 6-hydroxypyridoxine with respect to a variety of indices of vitamin B6 metabolism. By all criteria employed, 6-hydroxypyridoxine exhibited neither vitamin B6 nor antivitamin B6 activity and, thus, is nutritionally inert.     

Flavor Fade in Peanuts During Short-term Storage

ABSTRACT: Flavor characteristics of roasted peanuts over short-term storage were explored through sensory and chemical analyses. The volatiles from freshly roasted peanuts were evaluated over short-time (21 d) storage using gas chromatography, chemosensory techniques, and a sensory panel to quantify and identify pyrazines and hexanal over a 21-d storage period. A significant decrease ( P < 0.05) was noted in 2,3-diethylpyrazine, 2-methoxypyrazine, 2,3-dimethylpyrazine, 2-ethyl-3-methylpyrazine, and 2,3,5-trimethylpyrazine concentrations over a 21-d period. No significant difference ( P > 0.05) was noted in the 2-methylpyrazine and 2-ethylpyrazine concentrations. The hexanal concentration significantly increased ( P < 0.05) over the 21-d period. The peroxide values and sensory analysis agreed with these results. A significant increase ( P < 0.05) in peroxide value was seen at days 14 and 21, and a significant decrease ( P < 0.05) in fresh roasted peanuty flavor from day 0 to 21 and significant increases ( P < 0.05) in painty, cardboardy, and bitter flavors from day 7 to 21 with the sensory analysis. The electronic nose successfully separated day 0 and 21 samples from day 7 and 14 samples, which were also separated but with some overlap.     

Development of antimicrobial edible coating based on modified chitosan for the improvement of strawberries shelf life

Food Science and Biotechnology - Edible antimicrobial coating produced from chitosan (CS) and its derivative was applied to improve the shelf life of fresh strawberries at 10&nbsp;°C....