Consumer Preference and Sensory Properties of the Pacific Cupped Oyster (Crassostrea gigas) and the European Flat Oyster (Ostrea edulis)

ABSTRACT

Experts in the oyster supply chain (farmers, retailers, and gourmet chefs) in The Netherlands have suggested that the European flat oyster (Ostrea edulis) has superior sensory qualities compared to the Pacific cupped oyster (Crassostrea gigas). However, scientific evidence is lacking. The aim of this study was to evaluate consumer preferences for these two oyster species and to determine the sensory properties of both species by consumers. Two-alternative forced choice tests were performed with the oysters involving a panel of 74 naïve consumers. No significant differences in preferences between the oyster species were observed by the consumers. Nine sensory attributes of both oyster species were evaluated. Consumers did not observe significant differences between species in the sensory attributes: overall odor intensity, sea odor, mud odor, sweetness, pungency, and firmness. The Pacific cupped oyster was perceived as significantly saltier and more intense in greenness than the European flat oyster. We concluded that only a few sensory properties of the European flat oyster and the Pacific cupped oyster are perceived as being different by untrained consumers.     

Saltiness enhancement by taste contrast in bread prepared with encapsulated salt

In this study, we investigate a technological approach to reduce the sodium content of bread whilst retaining its sensory profile by creating taste contrast using encapsulated salt. We demonstrate that sensory contrast in bread induced by encapsulated salt can enhance saltiness and allows for a salt reduction of up to 50% while maintaining saltiness intensity. The magnitude of the saltiness enhancement depends on the size of the salt encapsulates. Small encapsulates lead to small concentration gradients of salt which do not affect saltiness intensity and consumer liking. Large encapsulates lead to large concentration gradients which enhance saltiness intensity significantly and reduce consumer liking. To achieve maximum salt reduction while maintaining saltiness and liking of the bread, the dimensions of the encapsulated salt particles need to be optimized. Taste contrast is a technology to modulate taste perception and to create sodium reduced products while retaining their saltiness intensity and consumer liking.     

AN IN-VITRO SCREENING METHOD TO STUDY THE ACTIVITY POTENTIAL OF BIOFERTILIZERS BASED ON TRICHODERMA AND BACILLUS SP.

Little scientific information on efficiency of different commercial biofertilizers restricts setup of further reproducible pot or field experiments and hence, provides lack of evidence of biofertilizer application in plant growth promotion and disease suppression. In the present experiment, efficiency of four commercial Trichoderma and one Bacillus biofertilizer was screened by a bio-indicator plant, cucumber (Cucumis sativus L.) under controlled laboratory conditions. Inoculation of cucumber seeds with different commercial biofertilizers significantly increased the germination rates (ca. 20–25%) and stimulated other growth parameters. In seedling establishment test, biofertilizers inoculated cucumber seedlings showed significant higher root dry weight (ca. 32 to 96%), leaf area (ca. 60 to 140%), root length (ca. 30%) and shoot dry weight (ca. 88%) in two weeks culture period compare to that of the control. Additionally, in-vitro antagonistic activity against take-all pathogen (Gaeumannomyces graminis var. tritici, Ggt) in wheat and phosphate solubilizing activity was demonstrated for Trichoderma biofertilizer. However, in-vitro solubilization of Mn was not detected. The results suggested that the potential activity of different commercial biofertilizers could be easily screened within several days with the described rapid bio-test by increasing seed germination, and improving growth and growth related parameters of cucumber grown in nutrient solution under controlled culture system.     

Preparation and comparative release characteristics of three anthocyanin encapsulation systems

Bilberries (Vaccinium myrtillus L.) and their major polyphenolic constituents, anthocyanins, have preventive activities inter alia against colon cancer and inflammatory bowel diseases. However, anthocyanins are sensitive to environmental conditions; thus their bioavailability in the gastrointestinal tract is an important determinant of their in vivo activity. In the study reported here, the potential benefits of encapsulating an anthocyanin rich bilberry extract (BE) on anthocyanin stability were investigated. Nonencapsulated BE and three different BE loaded microcapsule systems were incubated in simulated gastric fluid (SGF) and fed state simulated intestinal fluid (FeSSIF). After exposure to these media, released anthocyanins were identified and quantified by HPLC with UV/Vis detection. Although a rapid release of anthocyanins was observed within the first 20 min, encapsulation of anthocyanins doubled the amount of available anthocyanins after 150 min of incubation. These results illustrate the ability of encapsulation to inhibit early degradation of anthocyanins in the intestinal system.     

Assessment of ultrasound imaging as a noninvasive measure of blubber thickness in pinnipeds.

Portable ultrasound imaging was examined as a noninvasive measure of skin including blubber thickness in captive subadult Steller sea lions (Eumetopias jubatus) and adult harbor seals (Phoca vitulina). This method was validated through comparison with blubber biopsy. Ultrasound images provided depth measurements that were accurate to 99.8% of the actual. This method allowed clear images of the epidermis, dermis, and blubber layer to be rapidly obtained, with minimal animal restraint, and allowed differentiation of phocid and otariid blubber structure.     

Color, betalain pattern, and antioxidant properties of cactus pear (Opuntia spp.) clones

Total phenolics, ascorbic acid, and betalain contents of differently colored cactus pear clones (nine Opuntia ficus-indica [L.] Mill. clones and one O. robusta Wendl. clone) were investigated and related to their respective antioxidant potential assessed by Trolox-equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays. TEAC and ORAC values were very highly correlated with each other and also with values for total phenolics, betalain contents, and ascorbic acid concentrations. Total phenolics had the greatest contribution to ORAC and TEAC values. High-performance liquid chromatography (HPLC)-diode array detector (DAD)-tandem mass spectrometry (MS/MS) measurements of cactus pear juices permitted the differentiation of the clones based on variations in pigment patterns and betalain concentrations. The red and yellow betalains were absent in lime green colored cactus fruits. The ratio and concentration of these pigments were responsible for the yellow, orange, red, and purple colors in the other clones. Progeny of purple and lime green colored parents were characterized by 12% and 88% of plants bearing lime green and purple fruit, respectively. This implies that the genes for betalain production were lacking in the lime green fruits but could be provided by a parent with a complete set of genes, that is, purple fruits. Besides known pigments typical of Cactaceae, two unexpected betalains were identified. Whereas gomphrenin I was found for the first time in tissues of cactus plants, methionine-betaxanthin has never been described before as a genuine betalain. In addition to their alleged health-promoting properties, various combinations of yellow betaxanthins and red-purple betacyanins may allow the development of new food products without using artificial colorants.     

Effect of N and CO2 supply on source size per grain at anthesis and its relationship with grain growth in wheat

Rising atmospheric CO₂ concentration ([eCO₂]) increases the yield of wheat mainly by increasing grain number, but effects on single grain weight are variable. It is discussed whether single grain growth is limited by the sink or the source size under a non-stress environment. This study explores the effect of e[CO₂] combined with varying N supply on the source and sink size during grain filling. Source size was defined as the amount of stem reserves per grain (SRG) and the proportion of incident radiation intercepted by the green canopy per grain (f_IRG) at anthesis. Data from a 2-year free-air CO₂ enrichment experiment with wheat with three N levels (on average 38 [Nd], 190 [Nad] and 320 kg N ha⁻¹ [Nex]) and two CO₂ levels (393 and 600 ppm) on SRG, f_IRG and grain filling rate (GFR) and duration (GFD) were evaluated. SRG ranged from 2.5 to 12.9 mg and f_IRG from 4.0 × 0.001% to 6.8 x 0.001%. Rising N supply or e[CO₂] decreased SRG and f_IRG via their increases in grain number. Accordingly, there was a negative linear relationship between grain number and SRG (r² ≥ 0.84) or f_IRG (r² ≥ 0.97). Increasing N supply decreased GFR, but increased GFD, and GFR was increased by e[CO₂] under Nad and Nex. For GFR and final grain weight, there was a strong positive (r² ≥ 0.85), and for GFD, a strong negative linear relationship (r² ≥ 0.76) with f_IRG under Nad and Nex. Under these N levels, f_IRG supplied the largest share (>86%) for grain growth and thus single grain growth was possibly source limited under Nad and Nex. Under high grain number such as under Nex and e[CO₂], there might be a risk for low final grain weight due to the low SRG that is insufficient for buffering assimilate shortage under unfavourable environmental conditions in early grain filling.     

Below‐ground and above‐ground production of vegetational organic matter along a climosequence in alpine grasslands

The distribution of vegetational organic matter above‐ and below‐ground and its productivity was analyzed in an alpine area along a climosequence ranging from subalpine to alpine climates. Emphasis is placed on the quantification of carbon (C) and nitrogen (N) fixed in the above‐ground and below‐ground vegetation and its annual input. Annual C‐input ranged from 17.9 to 60.2 g m^—2 year^—1 and the N‐input from 0.74 to 2.48 g m^—2 year^—1. Above‐ground phytomass and the annual production rate of organic matter showed a distinct correlation with the altitude and, thus, the climate. However, the measurement of the above‐ground phytomass is bound to methodological problems: the commonly used harvesting method seems to underestimate the real situation. The harvesting method yielded in its average 100 to 300 g m^—2 phytomass which was 35—83% of the values obtained by the soil core method. Thus, the calculation of turnover times of above‐ground vegetation greatly depends on the method used. Calculated turnover times based on the harvesting method did not correlate with the climate while a clear tendency of lower turnover times with increasing altitude could be observed using the soil core method. The amount of below‐ground phytomass was in the range of 1880 to 2469 g m^—2 and the corresponding annual C‐input (fixation in the roots) between 91.1 and 162 g m^—2 year^—1 and the N‐input between 2.68 and 4.99 g m^—2 year^—1. The below‐ground phytomass and its production rate in high alpine zones are of greater importance and exceed the above‐ground ones. With increasing altitude, furthermore, the importance of the below‐ground phytomass increases with respect to the biomass and to the C‐ and N‐input. For high alpine areas, the phytomass is concentrated in the uppermost soil horizons. About 88.7 to 94.5% of the below‐ground phytomass was found in the soil compartment 0‐20 cm. The below‐ground production rate of phytomass in alpine grassland is fundamental in order to calculate any C or N budgets and potential inputs to SOM: its neglection would introduce most significant errors in modeling any C or N cycles.     

Flavor improvement in pork from barrows and gilts via inhibition of intestinal skatole formation with resistant potato starch

Skatole originates from microbial processing of tryptophan in the large intestine of pigs and accumulates in adipose tissue. Formation may be inhibited by the anti-apoptotic function of butyrate formed out of raw potato starch. Two groups of pigs (each consisting of gilts and barrows) were fed from 30 to 110 kg life weight either a conventional diet (controls; n = 35) or an isocaloric diet containing 300 g of raw potato starch/kg of body weight (RS; n = 34). Skatole concentrations were measured in colon content, blood, and adipose tissue. Odor of cooked meat samples was evaluated by a test panel. RS reduced concentrations in colon content and blood plasma (P < 0.001). Back fat concentrations were decreased significantly from 25 to 1.40 ng/g (barrows; P < 0.001) and from 40 to 9 ng/g (gilts; P < 0.001). Odor rating (scale of 1-5 from very unpleasant to very pleasant) was 3.07 for low skatole concentrations and 2.66 for both medium and high skatole concentrations (P < 0.05).     

Concordance of stream macroinvertebrate assemblage classifications: How general are patterns from single-year surveys?

We examined how the assemblage structure and assemblage-environment relationships of stream macroinvertebrates varied over three consecutive years in a boreal drainage system. We specifically examined whether classifications produced assemblage types that were stable through time, and how these assemblages could be predicted based on local environmental variables. We also used a combination of Procrustes rotation analysis and NMDS ordinations to examine the degree of year-to-year concordance of assemblage patterns. The composition of site clusters varied among years, resulting in only moderate among-year concordance of assemblage classifications. Stream width and in-stream habitat conditions, especially macrophyte cover, were the most important variables discriminating among the cluster groups. Despite temporally variable assemblage classifications, the overall macroinvertebrate assemblage structure was concordant among years. Among-year concordance was higher in-streams with low temporal variation in the physical environment, as well as high abundance and low variability of macrophytes. Due to among-year variability in cluster composition and weakly predictable assemblage-environment relationships, a posteriori assemblage classifications may be of limited value in the conservation planning of headwater streams.