Culture-specific variation in the flavor profile of soymilks

A modified quantitative descriptive analysis (QDA) method was used to determine sensory profiles of 8 soymilk products: 3 manufactured in Australia, 3 manufactured in Singapore, 1 manufactured in Malaysia, and 1 manufactured in Hong Kong. A panel (n= 7) was selected, trained in descriptive profiling of soymilk, and developed a soymilk language that was used to evaluate the flavor attributes of the soymilk products. A repeated-measure ANOVA showed highly reproducible panel performance, and significant differences in soymilk attributes among all soymilks. A principal component analysis (PCA) revealed 2 main groupings among the soymilks that corresponded to cultural origin: Australia and Asia (Singapore and Hong Kong/Malaysia). Products from Australia were significantly stronger in milky, astringent, salty notes and pale in color, while products from Asia were significantly stronger in beany, cooked beans, sweet, and pandan notes (P < 0.05). In addition, the Asian soymilks could be separated into 2 subgroups, with Singaporean soymilks having deeper color, greater viscosity, and less green flavor than Hong Kong/Malaysia soymilks. Australian produced soymilk is bovine-milk-like compared with Asian soymilk, presumably due to bovine milk being the primary source of milk in Australia. We conclude that culture-specific flavor preferences are a determining factor in flavor profiles of soymilks from geographically distinct regions.

Dietary manipulation of muscle long-chain omega-3 and omega-6 fatty acids and sensory properties of lamb meat

The effects of dietary manipulation of muscle long-chain omega-3 fatty acids (FA) on sensory properties of cooked meat in second cross ([Merino×Border Leicester]×Poll Dorset) wether lambs were evaluated. Lambs fed dietary supplements of fish meal (FM, Exp. 1) and fish oil (FO, Exp. 2) showed moderately (P<0.01) and markedly (P<0.001) increased muscle long-chain omega-3 FA content compared with those fed the basal diet of lucerne chaff and oat chaff. Protected canola seed (PCS, Exp. 1) significantly (P<0.001) increased omega-6 FA content of the longissimus muscle. In each of the 2 experiments (1 and 2), after being fed experimental diets for 6 weeks lambs were slaughtered at a commercial abattoir. At 24 h post-mortem (PM) the semitendinosus and biceps femoris muscles were removed from animals and stored at −20°C until evaluation of sensory properties using experienced panel members. The muscle samples were stored for 3 (Exp. 1) and 12 (Exp. 2) months then removed, thawed and cooked for sensory evaluation. The meat samples were cooked under standardized conditions in a convection microwave at 180°C (20–25 min) to an internal temperature of 75°C. Cooked samples were tested for flavour, aroma, juiciness and overall palatability. The significant increase in muscle long-chain omega-3 with FM (Exp. 1 and 2) and FO (Exp. 2) or omega-6 FA with PCS (Exp. 1) were not detrimental to sensory panel evaluations of flavour or aroma of cooked meat when compared with the basal diet. However, meat from FM (Exp. 1) had lower juiciness and FO (Exp. 2) had lower overall palatability. Protected sunflower meal protein with FO (Exp. 2) significantly lowered ratings for flavour, juiciness and overall palatability. Lamb meat with increased levels of long-chain omega-3 FA can be produced without altering the sensory quality (flavour or aroma) of the cooked meat.

Effect of prior exercise on glucose metabolism in trained men.

Several studies have demonstrated that oral glucose tolerance is impaired in the immediate postexercise period. A double-tracer technique was used to examine glucose kinetics during a 2-h oral glucose (75 g) tolerance test (OGTT) 30 min after exercise (Ex, 55 min at 71 ± 2% of peak O₂ uptake) and 24 h after exercise (Rest) in endurance-trained men. The area under the plasma glucose curve was 71% greater in Ex than in Rest (P = 0.01). The higher glucose response occurred even though whole body rate of glucose disappearance was 24% higher after exercise (P = 0.04, main effect). Whole body rate of glucose appearance was 25% higher after exercise (P = 0.03, main effect). There were no differences in total (2 h) endogenous glucose appearance (R_aE) or the magnitude of suppression of R_aE, although R_aE was higher from 15 to 30 min during the OGTT in Ex. However, the cumulative appearance of oral glucose was 30% higher in Ex (P = 0.03, main effect). There were no differences in glucose clearance rate or plasma insulin responses between the two conditions. These results suggest that adaptations in splanchnic tissues by prior exercise facilitate greater glucose output from the splanchnic region after glucose ingestion, resulting in a greater glycemic response and, consequently, a greater rate of whole body glucose uptake.

Sensory adaptability of foods with added Lupin (Lupinus angustifolius) kernel fibre using pre-set criteria

Fiber-enriched white bread, muffin. pasta, orange juice, and breakfast bar were prepared with lupin (Lupin us angusti/olius) kernel fiber. Consumer panelists (n = 44) determined that all these fiber-enriched foods, except orange juice, fulfilled pre-set acceptability criteria. Fiber enrichment did not change overall acceptability (p> 0.05) of the bread and pasta, but reduced overall acceptability (p < 0.05) of the muffin, orange juice, and breakfast bar. In all fiber-enriched products, flavor was the attribute most highly correlated with overall acceptability (p < 0.05). The lupin kernel fiber used in this study therefore appears to have potential as a 'nonintrusive' ingredient in some processed cereal-based foods_ For other applications, fiber modification appears worthy of investigation to accomplish 'nonintrusive' fiber enrichment.

Consumers` sensory and nutritional perceptions of three types of milk

Objective: To identify consumer perceptions of whole milk, reduced-fat milk and soy milk, and to investigate demographic influences on perceptions and types of milk consumption.

Design and setting: Questionnaires covering nutritional and sensory perceptions of three types of milk.

Subjects: Three hundred and sixty-one randomly selected shoppers in Melbourne, Australia.

Results: Generally, respondents held positive perceptions about milk. Milk was considered as having good sensory properties, providing a good source of nutrients, and being a convenient and safe product. However, despite these findings, misperceptions and unawareness about the nutrient content of milk were prevalent. Negative perceptions were most common for whole milk and were mostly related to its perceived high fat, cholesterol and energy contents. Soy milk received lower ratings on sensory quality and convenience than dairy milk. There were few sociodemographic differences in consumers' perceptions. Although reduced-fat milk consumption was more frequent among elderly people and type of milk consumption was related to parenthood, no other significant effects of demographic variables were found on the consumption of specific milk types.

Conclusion: Although positive perceptions were common, negative perceptions and misperceptions appear to be prevalent, presenting a challenge for nutrition education. Sociodemographic factors were not shown to be important predictors of perceptions and type of milk consumption.

Sensory acceptability of foods containing Australian sweet lupin (Lupinus angustifolius) flour

Foods containing Australian sweet lupin (Lupinus angustifolius) flour (ASLF) were assessed by consumer panelists (n= 54) in comparison to wheat flour (control) and defatted soy flour (DFSF) products. All ASLF products were rated in the acceptable half of the evaluation scale. General acceptability of ASLF chocolate chip cookies and breakfast bars was rated similarly to the control and DFSF variants (P > 0.05). ASLF pasta was rated lower than control but higher than DFSF pasta (P < 0.05), whereas ASLF addition reduced the general acceptability of muffins and bread (P < 0.05) compared with the other variants. Some ASLF products appeared palatable whereas ASLF incorporation rate in others requires reduction.

Growth of highly versus moderately trained competitive female artistic gymnasts

Purpose: To investigate whether growth was adversely affected in 137 young competitive female artistic gymnasts involved in different training volumes.

Methods: This was a 2-yr prospective cohort study in which height, sitting height, leg length, weight, skinfolds, and pubertal status were measured in competitive advanced (20–27 h·wk-1) and intermediate (7.5–22 h·wk-1) training level female gymnasts every 6–12 months. Biological parameters of the adolescent growth curve were estimated using the Preece–Baines growth model. Growth rates were estimated for both groups from the mixed-longitudinal data.

Results: Estimated ages at peak height velocity (PHV) (13–13.5 yr) and mean PHV (6.2–6.4 cm·yr-1) for the advanced- and intermediate-level gymnasts suggest that these gymnasts were later maturing and experienced a blunting of the growth spurt relative to reference values for U.S. youth. Comparison of growth velocities by pubertal status revealed that height velocity was lower in the advanced- versus the intermediate-level peripubertal gymnasts, which was due to a significant reduction in sitting height velocity (2.3 vs 3.1 cm·yr-1, P. < 0.05). No marked acceleration in height or sitting height velocity was detected in the advanced-level gymnasts from pre- to peripuberty. Inspection of individual growth rates revealed that over 35% of the pre- and peripubertal gymnasts experienced growth faltering (height velocity less than 4.5 cm·yr-1) during follow-up.

Conclusion: Advanced–and intermediate–training level competitive female gymnasts tend to exhibit an adolescent growth spurt that is similar in timing and tempo to short, normal, slowly maturing girls, but the high frequency of growth faltering suggests that training may alter the tempo of growth and maturation in some, but not all, female gymnasts.

The effects of short-term sprint training on MCT expression in moderately endurance-trained runners

The purpose of this study was to assess the effects of short-term sprint training on transient changes in monocarboxylate lactate transporter 1 (MCT1) and MCT4 protein and mRNA content. Seven moderately endurance-trained runners (mean ± SE; age 27.7±2.9 years, body mass 81.1±5.9 kg, VO₂ max 58.1±2.0 ml kg⁻¹ min⁻¹) completed a VO₂ max and a supramaximal running test to exhaustion (RTE) before and after a 6-week period of sprint training. The sprint training was progressive and consisted of 18 sessions of near maximal short duration (5–15 s) sprints to compliment the athlete’s endurance training. Prior to the training period there was a significant (P<0.05) increase in MCT1, but not MCT4 protein, 2 h after the RTE. This occurred without any change in corresponding mRNA levels. After the training period, there was a significant increase in MCT1 protein but no significant change in the MCT4 isoform. Both MCT1 and MCT4 mRNA was significantly lower at rest and 2 h post-RTE after the completion of the training period. After the training period, there was a significant increase in the time to exhaustion and distance covered during the RTE. This study demonstrates that sprint training of this length and type results in an upregulation of MCT1 protein, but not MCT4 content. Additionally, this study shows conflicting adaptations in MCT1 and MCT4 protein and mRNA levels following training, which may indicate post-transcriptional regulation of MCT expression in human muscle.

Lipotoxicity: the obese and endurance-trained paradox

The potential lipotoxic effect of intramyocellular triglyceride (IMTG) accumulation has been suggested to be a major component in the development of insulin resistance. Increased levels of IMTGs correlate with insulin resistance in both obese and diabetic patients, but this relationship does not exist in endurance trained (ETr) subjects. This may be, in part, related to differences in the gene expression and activities of key enzymes involved in fatty acid transport and oxidation as well as in the perodixation status of the IMTGs in obese/diabetic patients as compared with ETr subjects. Disruptions in fat and lipid homeostasis in skeletal muscle have been shown to activate protein kinase C (PKC), which acts on several downstream signalling pathways, including the insulin and the IB kinase (IKK)/NFB signalling pathways. Additionally, an increased peroxidation of IMTGs may reduce insulin sensitivity by increasing TNF, which is known to increase the expression of suppressor of cytokine signalling proteins (SOCS). A common characteristic observed when activating both PKC and TNF/SOCS3 is the inhibition of tyrosine phosphorylation of IRS-1 and subsequently an inhibition of its activation of downstream signalling molecules. These may be important players in the development of insulin resistance and understanding their activation and expression in both obese and ETr humans should assist in understanding how and why IMTGs become lipotoxic.

Lipid peroxidation in skeletal muscle of obese as compared to endurance-trained humans: a case of good vs. bad lipids?

Intra-myocellular triglycerides (IMTG) accumulate in the muscle of obese and endurance-trained (ET) humans and are considered a pathogenic factor in the development of insulin resistance, in the former. We postulate that this paradox may be associated with the peroxidation status of the IMTG. IMTG content was the same in the obese and ET subjects. The lipid peroxidation/IMTG ratio was 4.2-fold higher in the obese subjects. Hence, obesity results in an increased level of IMTG peroxidation while ET has a protective effect on IMTG peroxidation. This suggests a link between the lipid peroxidation/IMTG ratio and insulin resistance.

Consumer acceptability of low fat foods containing inulin and oligofructose

Inulin and oligofructose were used as fat replacers in Anzac cookies, blueberry muffins, carrot cake, chocolate cake, lemon cheesecake, ice cream, and beef sausages at levels ranging from 4 to 13g/100g, achieving a significant reduction in fat content (20% to 80% relative). These foods were rated as acceptable by an untrained taste panel, but scored consistently lower than their full-fat counterparts (controls). Regression analysis showed that, unlike the controls, texture was more important than flavor in determining overall acceptability of the low-fat foods. Inulin and oligofructose are readily incorporated into bakery and meat formulations, but their use might be limited by adverse physiological effects when consumed at high levels.

Effects of alternative dietary lipid sources on performance, tissues chemical composition, mitochondrial fatty acid oxidation capabilities, and sensory characteristics in brown trout (Salmo trutta L.)

The efficiency of five dietary lipid sources (fish oil as control—C; canola oil—CO; poultry fat—PF; pork lard—PL; and oleine oil—OO) were evaluated in juvenile brown trout (58.4±0.7 g) in an experiment conducted over 70 days at 14.6±0.4 °C. The best growth was observed in fish fed the C diet whereas the PL diet fed fish had the best feed utilization. Significant differences in carcass and muscle proximate composition, but not in liver, were noted among fish fed the different dietary treatments. The fatty acid composition of muscle largely reflected that of the diets, while total cholesterol was not affected. The atherogenicity and the thrombogenicity qualities of the trout flesh were modified by the lipid sources. Sensory analysis did not show any significant differences among the cooked fillets with respect to dietary treatments, while in uncooked products, some significant differences were observed. The carnitine palmitoyltransferase I and II (CPT-I and CPT-II) activities of liver and white muscle were assayed for a better understanding of the potential β-oxidation capability of the different dietary lipid sources. The hepatic, but not white muscle CPT-I and CPT-II activities were affected by dietary treatments. This study showed that alternative lipid sources could be used effectively for oil coating extruded diets for brown trout.