Two unsaturated fatty acids with potent α-glucosidase inhibitory activity purified from the body wall of sea cucumber (Stichopus japonicus)

One therapeutic approach for preventing diabetes mellitus and obesity is to retard the absorption of glucose via inhibition of α-glucosidase. Two unsaturated fatty acids with strong α-glucosidase inhibitory activity, 7(Z)-octadecenoic acid (1) and 7(Z),10(Z)-octadecadienoic acid (2), were purified from the body wall of Stichopus japonicus. IC(50) values of compounds 1 and 2 were 0.51 and 0.67 μg/mL against Saccharomyces cerevisiae α-glucosidase and 0.49 and 0.60 μg/mL against Bacillus stearothermophilus α-glucosidase, respectively. These compounds mildly inhibited rat-intestinal sucrase and maltase. In addition, both compounds showed a mixed type of inhibition against S. cerevisiae α-glucosidase and were very stable under thermal and acidic conditions up to 60 min. The K(I) and K(IS) values of compounds 1 and 2 were 0.44 and 0.22 μg/mL, and 0.39 and 0.13 μg/mL, respectively. PRACTICAL APPLICATION: One therapeutic approach for preventing diabetes mellitus is to retard the absorption of glucose via inhibition of α-glucosidase. In this study, 2 fatty acids with strong α-glucosidase-inhibitory activity, 7(Z)-octadecenoic acid and 7(Z),10(Z)-octadecadienoic acid, were purified and identified from sea cucumber. Therefore, sea cucumber fatty acids can potentially be developed as a novel natural nutraceutical for the management of type-2 diabetes.     

Revisiting Fisher’s ‘Lady Tasting Tea’ from a perspective of sensory discrimination testing

The Lady Tasting Tea is a famous real story in the history of development of statistics, related to R.A. Fisher, one of the greatest statisticians and founders of modern statistics. The main learning and insight offered by this paper from revisiting the story are that the methodology of conventional sensory difference tests can be and should be expanded to cover the ‘M + N’ method with larger M and N. Unlike the conventional discrimination tests, which use multiple sets of ‘M + N’ samples with small M and N based on a binomial model, the ‘M + N’ tests with larger M and N can reach a statistical significance in a single trial using only one set of ‘M + N’ samples based on a hypergeometric distribution in Fisher’s exact test. This paper explores the applications of the new methods particularly in assessing performance of trained sensory panels and panelists. The connection of the odds ratio or common odds ratio with Cohen’s standardized mean difference d is also discussed.     

Recovery of protein hydrolysates from brewer’s spent grain using enzyme and ultrasonication

The aim of this study was to develop a green ultrasound-assisted enzymatic process to separate protein from brewer’s spent grain (BSG) to produce protein hydrolysates and determine the physicochemical properties of produced protein hydrolysates. When the enzyme (Alcalase) loading increased from 1 to 20 μL g⁻¹ BSG, the protein separation efficiency increased from 34.0% to 61.6%. The application of ultrasound pretreatment further increased protein separation efficiency to 69.8%. More promisingly, the ultrasound pretreatment was able to reduce enzyme loading by 73% and decrease enzyme incubation time by 56%. The produced protein hydrolysates had molecular weights lower than 15 kDa and high protein solubilities at the pH of 1.0–11.0. The ultrasound pretreatment improved the protein solubility to above 90%. Glutamic acid and proline were the most abundant amino acids in produced protein hydrolysates. This study demonstrated that enzymatic hydrolysis along with ultrasound pretreatment is an effective way to separate protein from BSG.     

Temperature-Dependent Dielectric Properties of Raw Cow’s and Goat’s Milk from 10 to 4,500 MHz Relevant to Radio-frequency and Microwave Pasteurization Process

To offer useful information for milk pasteurization with radio-frequency or microwave heating, the dielectric properties (dielectric constant and dielectric loss factor) of raw cow’s milk and goat’s milk were determined over the frequency range of 10–4,500 MHz and temperature range of 25–75 °C by a vector network analyzer and an open-ended coaxial-line probe. The mathematical models describing the relationship between permittivities and temperature were built, and the power penetration depth was investigated. The results showed that both for cow’s milk and goat’s milk, the dielectric constants decreased with an increase of frequency, and the dielectric loss factor decreased with increasing frequency below 1,000 MHz and increased after that. The dielectric constants decreased with increasing temperature at a given frequency. For raw cow’s milk, the dielectric loss factor almost increased with temperature below about 800 MHz, and decreased with temperature above that. For raw goat’s milk, the loss factor decreased with temperature in whole investigated frequency range. Quadratic equations could be used to describe the relationship between permittivities and temperature at interested frequencies with coefficient of determination higher than 0.96. The penetration depth decreased with increasing frequency. Contrasted to frequency, temperature had less effect on penetration depth. Microwave heating at 915 MHz has great potential for raw cow’s milk pasteurization, while radio-frequency heating at 27.12 and 40.68 MHz and microwave heating at 915 MHz can be used for goat’s milk pasteurization.     

Sounds sweet,sounds bitter: How the presence of certain sounds in a brand name can alter expectations about the product’s taste

This paper examines how certain speech sounds within a brand name can alter expectations about the product’s taste. Across two studies we demonstrate that the presence of voiced (b, d, g, z & v) vs. voiceless (p, t, k, s & f) obstruents (speech sounds produced when airflow is obstructed in the oral cavity) in a chocolate’s brand name can alter its expected taste as bitter vs. sweet. We propose this is because voiced obstruents are typically of low frequency (frequency code hypothesis), contain harsh acoustic qualities and evoke negativity (due to aerodynamic difficulties in their pronunciation). In a third study, we extend these findings to show, using the Brand Personality Scale (BPS), that the presence of voiced (vs. voiceless) obstruents makes brand names' sound more masculine, rugged and tough and less honest, charming, glamorous, wholesome, cheerful and sentimental. Research linking consonant sound symbolism (specifically voiced obstruents) and product attributes is sparse. Most research in this field links vowels withproduct attributes, sounds with shapes and music (or musical notes) with taste attributes. We contribute by extending these findings to voicing (and associated harshness) and the sweet-bitter continuum of the expected taste.     

Effect of Different Cooking Conditions on the Pasting Properties of Flours of Glutinous Rice Varieties from Lao People’s Democratic Republic

The effect of different rehydration temperatures (30, 40, and 50°C) and cooking times (2.7, 4.7, 6.7, 8.7, and 10.7 min) at 95°C on the pasting properties of three glutinous varieties (Thadokkham-11, Thadokkham-8, and Hom Mali Niaw) from Lao People’s Democratic Republic was investigated using rapid visco analyzer. Non-glutinous varieties (IR64 and Doongara) were also analyzed to compare glutinous (amylose <4.5%) and non-glutinous (amylose >15%) varieties. All rice flours took up water at significantly (p < 0.05) higher rates in the case of increased temperature and soaking time, resulting in a decrease in the onset temperature for pasting. Among the glutinous rices, Thadokkham-8 showed a significant (p < 0.05) decrease in peak viscosity in response to increased rehydration time and temperature. For this variety maximum viscosity (2403.3 mPas) was observed at 1 min of rehydration at 30°C and minimum viscosity (1852.0 mPas) at 15 min of rehydration at 50°C. The viscosity values of Thadokkham-11 and Hom Mali Niaw varieties increased to their highest values (1608.7 and 1477.7 mPa.s, respectively) with an increase in temperature to 40°C for 1 min. In general, the glutinous rices produced weaker gel than non-glutinous rices. Extended holding at cooking temperature (95°C) had a more significant (p < 0.05) effect on the glutinous varieties Thadokkham-8 and Thadokkham-11 than on the non-glutinous varieties (IR64 and Doongara) used in this study.     

Phytanic acid concentrations and diastereomer ratios in milk fat during changes in the cow’s feed from concentrate to hay and back

The phytanic acid content in milk correlates with the amount of green items in the cows’ feed. For this reason, the four-fold methyl-branched fatty acid has been suggested as a potential marker for the authentication of organic milk. In this study, we attempted to provide further support for this idea by studying the progression of the phytanic acid level and diastereomer ratio in milk fat by transition of the diets from high proportions of concentrate (typical “conventional” feed) to hay (typical “organic” feed in winter) and back to “conventional” feed. Milk samples taken from three cows were analyzed on both the phytanic acid concentration and diastereomer distribution. The cows were initially fed with “conventional” feed (ground feed with high portions (30–45?%) of concentrate), then the feed was changed within 1?week to 100?% hay (“organic” feed), and after ~6?weeks, the feed of two cows was changed back to the initial feed with concentrate (phase C_b). During the “conventional” feeding at the beginning of the experiment, the phytanic acid concentration was low (100–130?mg/100?g milk fat). When the feed was changed to hay (“organic” feed), the phytanic acid concentration immediately increased to a stable level of about 160?mg/100?g lipids. Changing back the feed to “conventional” feed, the phytanic acid concentration dropped immediately back below the value measured in the initial phase. Likewise, the SRR/RRR-diastereomer distribution of phytanic acid in the milk was an excellent indicator for the changes in the cows’ feed. While the SRR/RRR-diastereomer ratio was >1.5 during “conventional” feeding, it immediately decreased to equal amounts of both diastereomers when hay was supplied as feed. Abandonment of concentrate in conventional feeding increased the phytanic acid content but the SRR-diastereomer was still dominant and thus the SRR/RRR-diastereomer ratio was different to organic milk. Our results indicate that both parameters, i.e., the phytanic acid content and SRR/RRR-diastereomer ratio need to be measured for authentication of organic milk.     

Isolation of xanthones from adventitious roots of St. John’s Wort (Hypericum perforatum L.) and their antioxidant and cytotoxic activities

In this phytochemical study, 5 xanthones, 1,3,5,6-tetrahydroxyxanthone [1], 1,5,6-trihydroxy-3-methoxyxanthone [2], ferrxanthone [3], brasilixanthone B [4], and neolancerin [5] were isolated from adventitious roots of St. John’s wort (Hypericum perforatum L.). Compound 1–5 were evaluated for antioxidant activities using the intracellular reactive oxygen species (ROS) radical scavenging 2′,7′-dichlorfluorescein-diacetate (DCFDA) assay and for cytotoxic activity against the HL-60 human promyelocytic leukemia cells. Among them, compound 1–4 exhibited scavenging activity with inhibition values of 27.4–33.2% at 10 μM; compound 1, 2, and 4 reduced the viability of HL-60 cells significantly, with IC₅₀ values of 31.5, 28.9, and 27.7 μM, respectively.