Inulin‐type fructans and whey protein both modulate appetite but only fructans alter gut microbiota in adults with overweight/obesity: A randomized controlled trial

Scope

Independently, prebiotics and dietary protein have been shown to improve weight loss and/or alter appetite. Our objective was to determine the effect of combined prebiotic and whey protein on appetite, body composition and gut microbiota in adults with overweight/obesity.

Methods and results

In a 12 week, placebo‐controlled, double‐blind study, 125 adults with overweight/obesity were randomly assigned to receive isocaloric snack bars of: (1) Control; (2) Inulin‐type fructans (ITF); (3) Whey protein; (4) ITF + Whey protein. Appetite, body composition and gut microbiota composition/genetic potential were assessed. Compared to Control, body fat was significantly reduced in the Whey protein group at 12 wks. Hunger, desire to eat and prospective food consumption were all lower with ITF, Whey protein and ITF + Whey protein compared to Control at 12 wks. Microbial community structure differed from 0 to 12 wks in the ITF and ITF +Whey Protein groups (i.e. increased Bifidobacterium ) but not Whey Protein or Control. Changes in microbial genetic potential were seen between Control and ITF‐containing treatments.

Conclusion

Adding ITF, whey protein or both to snack bars improved several aspects of appetite control. Changes in gut microbiota may explain in part the effects of ITF but likely not whey protein.

     

Ser71 of αS1‐Casein is Phosphorylated in Breast Milk—Evidence from Targeted Mass Analysis

Scope

The casein phosphoproteins in mother's milk supply calcium and phosphate ions and make them biologically available to the newborn. Human αS1‐casein is of particular interest being also an autoantigen and proinflammatory cytokine. Phosphorylation of αS1‐casein by casein kinase 2 completely abolishes binding to toll‐like receptor 4 and proinflammatory effects. It is, however, not known, which amino acids are affected. Therefore, breast milk samples were analyzed in an effort to detect the phosphorylation sites of αS1‐casein.

Methods and results

Breast milk samples were tryptically digested. Target tandem MS analysis confirmed the known phosphorylation sites S33 and S41; evidence for pS89 was found in some samples. Experimental support for the presence of pS31 and pS34 was weak. Phosphorylation of a new site in αS1‐casein, S71, was reproducibly measured in all samples, albeit at much lower intensity than pS33 and pS41.

Conclusion

Phospho‐occupancy rates varied greatly and could not be confidently correlated to other parameters within the cohort of 20 donors. The new phosphosite S71 is located in the neighborhood of the serine‐rich region and may contribute to the cluster of high charge density at normal milk pH, likely exerting an influence on protein tertiary structure and thus function.

     

PHYSICAL PROPERTIES OF FISH PROTEINS COOKED WITH STARCHES OR PROTEIN ADDITIVES UNDER OHMIC HEATING

ABSTRACT

The texture, color and microstructure of surimi seafood gels were investigated to determine the interaction effects of fish proteins with starches or protein additives under ohmic heating, and to compare ohmically cooked gels with conventional water‐bath‐cooked gels. Gel properties were affected by the type of additive, concentration and cooking method. The effect of starch on gel texture was more pronounced at low concentrations. Compared to wheat starch, potato starch seemed to slightly improve gel strength; however, it decreased the gel whiteness. All nonfish protein additives resulted in better or equal textural properties of gels, whereas there was a slightly negative effect for gel color. Fast ohmic‐cooked gels mostly exhibited higher gel strength than conventionally cooked gels.

PRACTICAL APPLICATIONS

There is a discrepancy between current gel preparation (slow heating by water bath) and current practice of crabstick manufacturing (fast heating). The use of data generated from slow cooking gel preparation for the manufacture of fast cooking crabstick does not make sense. This study demonstrates how starch and protein additives behave at ohmic heating which mimics the fast cooking crabstick manufacture.

     

Relationship between vitamin D and gestational diabetes in overweight or obese pregnant women may be mediated by adiponectin

Scope

Maternal vitamin D deficiency has been implicated in adverse pregnancy outcomes. However, the association between vitamin D and inflammation, particularly adipokines, remains unexplored in pregnancy.

Methods and results

In 102 overweight or obese pregnant women at high‐risk of gestational diabetes mellitus (GDM), we investigated relationships between maternal 25‐hydroxyvitamin D (25(OH)D) concentrations at 12–15 wk gestation (baseline) and serum lipids, inflammatory markers, novel adipokines (omentin‐1, visfatin, high molecular weight (HMW) adiponectin), and subsequent pregnancy outcomes (GDM, preeclampsia, preterm birth [PTB]). After adjustment for maternal factors (age, BMI, parity, ethnicity, and smoking status), baseline 25(OH)D concentrations were inversely associated with total cholesterol and triglycerides, and positively associated with HMW‐adiponectin. Higher baseline 25(OH)D concentrations were associated with decreased fasting and 1‐h post‐OGTT glucose and reduced risk of GDM at 26–28 wk, as well as with longer gestation and reduced risk of PTB upon additional adjustment for caesarean section. Adding HMW‐adiponectin to the multivariable models attenuated most associations, and HMW‐adiponectin was a significant predictor in the models.

Conclusion

Our findings suggest that lower maternal 25(OH)D concentrations in overweight/obese pregnant women at high‐risk of GDM are associated with increased cardiometabolic risks during pregnancy and adverse pregnancy outcomes, and that these associations may be mediated by HMW‐adiponectin.

     

Processing of cauliflower by ohmic heating: influence of precooking on firmness

The feasibility of processing cauliflower by ohmic heating was investigated. Firstly, cauliflower florets were precooked in tap water at low temperatures (40–70 °C) for 0 to 60 min. A control sample was cooked at 95 °C for 5 min. No significant textural differences were found between samples treated at 40 or 50 °C and fresh samples, but the firmness of samples cooked above 60 °C decreased. The effect of precooking time was not found to be significant. Secondly, low temperature precooking was performed in salted water for 30 min and followed by ohmic heating (holding time 30 s at 135 °C). After ohmic heating, florets pretreated at low temperatures were firmer than control samples. The firmness of florets precooked at 40 °C or 50 °C was considerably increased (>300%) compared to those precooked at 95 °C. Low-temperature precooking increased the firmness of cauliflower subjected to ohmic heating. The experimental results show that ohmic heating combined with low-temperature precooking in saline solutions offers a viable solution to high temperature/short time sterilisation of cauliflower florets. © 1999 Society of Chemical Industry     

Urinary Excretion of Niacin Metabolites in Humans After Coffee Consumption

Scope

Coffee is a major natural source of niacin in the human diet, as it is formed during coffee roasting from the alkaloid trigonelline. The intention of our study was to monitor the urinary excretion of niacin metabolites after coffee consumption under controlled diet.

Methods and results

We performed a 4‐day human intervention study on the excretion of major niacin metabolites in the urine of volunteers after ingestion of 500 mL regular coffee containing 34.8 μmol nicotinic acid (NA) and 0.58 μmol nicotinamide (NAM). In addition to NA and NAM, the metabolites N¹‐methylnicotinamide (NMNAM), N¹‐methyl‐2‐pyridone‐5‐carboxamide (2‐Py), and nicotinuric acid (NUA) were identified and quantified in the collected urine samples by stable isotope dilution analysis (SIVA) using HPLC‐ESI‐MS/MS. Rapid urinary excretion was observed for the main metabolites (NA, NAM, NMNAM, and 2‐Py), with t_max values within the first hour after ingestion. NUA appeared in traces even more rapidly. In sum, 972 nmol h^?1 of NA, NAM, NMNAM, and 2‐Py were excreted within 12 h after coffee consumption, corresponding to 6% of the ingested NA and NAM.

Conclusion

The results indicate regular coffee consumption to be a source of niacin in human diet.

     

Response of Red Blood Cell Folate to Supplementation in Nonpregnant Women is Predictable: A Proposal for Personalized Supplementation

Scope

We modeled red blood cell (RBC)‐folate response to supplementation and developed personalized folate supplementation concepts.

Methods and results

The changes of RBC‐folate were modeled in a time‐ (4 or 8 weeks) and dose‐ (400 or 800 μg d^?1 folate) dependent manner. Post‐supplementation RBC‐folate levels were predicted from folate‐loading capacities (= measured RBC‐folate – [baseline RBC‐folate × RBC‐survival]). The prediction equations were validated in 119 participants. The median increase of RBC‐folate was higher in the 800 μg d^?1 than in the 400 μg d^?1 group (275 vs 169 nmol L^?1 after 4 weeks, and 551 vs 346 nmol L^?1 after 8 weeks). Medians (interquartile range) of RBC‐folate loading were (4 weeks: 299 (160) vs 409 (237) nmol L^?1) and (8 weeks: 630 (134) versus 795 (187) nmol L^?1) in the 400 and 800 μg d^?1 group, respectively. The individual measured and predicted RBC‐folate values (after 4 weeks/400 μg d^?1 = 25 + 1.27 × baseline RBC‐folate) and (after 4 weeks/800 μg d^?1 = 65 + 1.41 × baseline RBC‐folate) did not differ significantly. The measured and predicted concentrations showed high agreement in the validation cohort.

Conclusions

The models can guide nutritional recommendations in women when baseline RBC‐folate concentrations are measured and the time to pregnancy between 4 and 8 weeks.

     

ANALYSIS OF TEXTURE OF BONELESS, FULLY FRIED BREADED CHICKEN PATTIES AS AFFECTED BY PROCESSING FACTORS

ABSTRACT

Battered and breaded, fully cooked, boneless chicken patties were analyzed based on processing variables (substrate, breading, rethermalization method, shape) and six objective texture attributes. Analysis of variance compared both individual samples and main effects, while statistical cluster analysis classified products based on their independent characteristics and the objective texture attributes. One sample (baked, crackermeal, all meat, nuggets) was significantly higher in most textural attributes. The soy‐containing samples were texturally similar. Breading and shape were not significantly different for the main effects of crust fracture force and work. Samples were sorted into clusters: cluster 1 characterized by oat bran breading, cluster 2 by crackermeal breading and soy‐containing substrate, cluster 3 by crackermeal and all‐meat substrate, and cluster 4 by Japanese bread crumbs and patty shape. Statistically classifying breaded chicken patties could lead to the development of a reliable, statistically based and easy‐to‐implement process that would aid quality control and product development in the meat industry.

PRACTICAL APPLICATIONS

Characterization of the textural attributes of breaded meat patties such that differentiation could be achieved with a common instrument (texture analyzer) could provide a reliable and easy‐to‐implement method to assess the quality of texture in meat products that would be beneficial to the meat industry for both quality control and product development purposes.

     

Effect of substituting fresh‐cut perennial ryegrass with fresh‐cut white clover on bovine milk fatty acid profile

BACKGROUND

Including forage legumes in dairy systems can help address increasing environmental/economic concerns about perennial ryegrass monoculture pastures. This work investigated the effect of substituting fresh‐cut grass with increasing quantities of fresh‐cut white clover (WC) on milk fatty acid (FA) profile and transfer efficiency of dietary linoleic (LA) and α‐linolenic (ALNA) acids to milk fat. Three groups of three crossbred dairy cows were used in a 3 × 3 crossover design. Dietary treatments were 0 g kg^?1 WC + 600 g kg^?1 grass, 200 g kg^?1 WC + 400 g kg^?1 grass, and 400 g kg^?1 WC + 200 g kg^?1 grass. All treatments were supplemented with 400 g kg^?1 concentrates on a dry matter basis. Cows had a 19‐day adaptation period to the experimental diet before a 6‐day measurement period in individual tie stalls.

RESULTS

Increasing dietary WC did not affect dry matter intake, milk yield or milk concentrations of fat, protein or lactose. Milk polyunsaturated FA concentrations (total n‐3, total n‐6, LA and ALNA) and transfer efficiency of LA and ALNA were increased with increasing dietary WC supply.

CONCLUSION

Inclusion of WC in pastures may increase concentrations of nutritionally beneficial FA, without influencing milk yield and basic composition, but any implications on human health cannot be drawn. © 2018 The Authors. Journal of the Science of Food and Agriculture published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.

     

Lipid oxidation and colour in pressure‐ and heat‐treated minced chicken thighs

Lipid oxidation and colour in pressurised and heated chicken samples were evaluated. In a preliminary test, raw and overcooked (100 °C/60 min) minced chicken thighs were pressurised (500 MPa/50 °C/30 min). Samples were stored at 4 °C in contact with air. Thiobarbituric acid reactive substances (TBARS) were quantified at 1, 6 and 9 days. Pressure induced oxidation in chicken, but overcooking generated many more secondary oxidation compounds. In a second experiment, raw minced chicken thighs were pressurised (500 MPa/?10, 5, 20 and 50 °C/30 and 60 min) or cooked (90 °C/15 min). Samples were vacuum stored at 4 °C. TBARS were measured at 1 and 9 days, whereas colour parameters (L, a, b and ΔE) were determined at 1 day. No differences in TBARS values were observed between untreated and pressurised samples, whereas cooked samples presented the highest values. Pressurisation for 30 and 60 min generated similar TBARS contents. At 9 days, oxidation values did not increase. Pressurisation and cooking induced marked colour changes. Pressurised samples were lighter and less red than untreated ones. Samples pressurised at 50 °C were the palest and, together with cooked samples, presented the lowest a values. Therefore pressurised chicken thigh cannot be marketed as a fresh product but can be incorporated as an ingredient in ready‐to‐eat meals. Copyright © 2004 Society of Chemical Industry     

Clinical and Vitamin Response to a Short‐Term Multi‐Micronutrient Intervention in Brazilian Children and Teens: From Population Data to Interindividual Responses

Scope

Micronutrients are in small amounts in foods, act in concert, and require variable amounts of time to see changes in health and risk for disease. These first principles are incorporated into an intervention study designed to develop new experimental strategies for setting target recommendations for food bioactives for populations and individuals.

Methods and results

A 6‐week multivitamin/mineral intervention is conducted in 9–13 year olds. Participants (136) are (i) their own control (n‐of‐1); (ii) monitored for compliance; (iii) measured for 36 circulating vitamin forms, 30 clinical, anthropometric, and food intake parameters at baseline, post intervention, and following a 6‐week washout; and (iv) had their ancestry accounted for as modifier of vitamin baseline or response. The same intervention is repeated the following year (135 participants). Most vitamins respond positively and many clinical parameters change in directions consistent with improved metabolic health to the intervention. Baseline levels of any metabolite predict its own response to the intervention. Elastic net penalized regression models are identified, and significantly predict response to intervention on the basis of multiple vitamin/clinical baseline measures.

Conclusions

The study design, computational methods, and results are a step toward developing recommendations for optimizing vitamin levels and health parameters for individuals.

     

Influence of vegetable shortening and emulsifiers on the unfrozen water content and textural properties of frozen French bread dough

The influence of vegetable shortening (VS) and emulsifiers (calcium stearoyl-2-lactylate (CSL) and polysorbate 80 (PS80)) on frozen French bread dough has been studied. Eight formulations without yeast were used with different quantities of VS, CSL and PS80. Dough was prepared by mixing all ingredients in a dough mixer at two speeds. The fresh dough was divided into 60 g pieces and molded. Fresh dough samples were also collected for water content and textural analyses. The dough pieces were packed, frozen in a freezer at −30°C and stored at −18°C up to 56 days. After 2, 7, 21, 28 and 56 days of frozen storage, samples were removed from the freezer, thawed at ambient temperature and textural analyses were conducted.The enthalpy of freezable water on fresh bread dough was determined by Differential Scanning Calorimetry (DSC) at the heating rate of 3°C/min, temperature range of −40°C to 20°C. The value of unfrozen water was 0.30–0.34 g H₂O/g solids and additives used during the storage up to 56 days significantly affected the textural properties of frozen dough.     

Quality properties and formation of α-dicarbonyl compounds in abalone muscle (<Emphasis Type="Italic">Haliotis discus</Emphasis>) as affected by tenderization and baking processes

Abalone is one of the most valuable seafood products and the quality of ready-to-eat abalone products could be improved through tenderization treatments prior to a fully cooking process. In this study, a tenderization process (80 °C for 2 h) was applied to improve the quality properties of baked abalone muscle for the developing of ready-to-eat products. The quality properties of baked abalone (150–210 °C, 10–30 min) with and without pre-tenderization treatment prior to baking were evaluated through sensory evaluation, textural analysis and Hunter Lab colorimeter. In addition, amounts of sugars and α-dicarbonyl compounds in these products were determined via HPLC analyses. The baking condition at 180 °C for 20 min combined with pre-tenderization resulted in an optimal product. The baked abalone with pre-tenderization had better textural properties (hardness, 1031.12?±?101.67; springiness, 0.96?±?0.02; chewiness, 817.13?±?113.43; shear, 2843.92?±?35.67), sensory scores (30.1?±?2.9) and color (25.28?±?1.21) as compared to the baked abalone without pre-tenderization (hardness, 1990.91?±?252.35; springiness, 0.87?±?0.01; chewiness, 1164.43?±?195.64; shear, 3910.79?±?302.12; sensory score, 17.4?±?1.0; color, 15.91?±?0.74). The reducing sugar analysis indicated the presence of ribose and glucose in the baked abalone. In addition, the formation of α-dicarbonyl compounds (degraded from reducing sugars) including glucosone, 3-deoxyglucosone, glyoxal, methylglyoxal, and diacetyl were significantly promoted by the tenderization process in the baked abalone muscle. And the tenderization treatment led to an average of 218% increase in α-dicarbonyl compounds in the baked abalone muscle. The promotion of the formation of α-dicarbonyl compounds by the tenderization treatment contributed to the accumulation of pigments in the final baked products and led to desirable color.     

Theobromine Does Not Affect Fasting and Postprandial HDL Cholesterol Efflux Capacity,While It Decreases Fasting miR‐92a Levels in Humans

Scope

Chocolate consumption lowers cardiovascular disease risk, which might be attributed to the methylxanthine theobromine. These effects may be mediated through effects on HDL‐mediated cholesterol efflux, which may be affected by microRNA (miRNA) levels in the HDL particles. Therefore, the aim of this study is to investigate effects of theobromine consumption on fasting and postprandial cholesterol efflux and miRNAs levels.

Methods and results

Thirty overweight and 14 obese healthy men and women participated in this randomized, double‐blind crossover study. Participants consumed 500 mg d^?1 of theobromine or placebo for 4 weeks. ABCA1‐mediated cholesterol efflux was measured using J774 macrophages. MiRNAs levels (miR‐92a, miR‐223, miR‐135a*) were quantified in apolipoprotein B‐depleted serum. Theobromine consumption did not affect fasting and postprandial cholesterol efflux. Fasting miR‐223 and miR‐135a levels were unchanged, while miR‐92a levels were decreased (?0.21; p < 0.05). The high‐fat meal increased postprandial cholesterol efflux capacity (+4.3 percentage points; p ≤ 0.001), miR‐92a (+1.21; p < 0.001), and miR‐223 (+1.79; p < 0.001) levels, while a trend was found for miR‐135a (+1.08; p = 0.06).

Conclusion

Theobromine did not improve fasting and postprandial ABCA1‐mediated cholesterol efflux capacity, but decreased fasting miR‐92a levels. High‐fat meal intake increased postprandial cholesterol efflux and the three selected miRNAs levels.

     

Gel‐forming ability of surimi from grass carp (Ctenopharyngodon idellus): influence of heat treatment and soy protein isolate

The effects of setting conditions and soy protein isolate (SPI) on textural properties of surimi produced from grass carp were investigated. Effects of setting temperature, setting time and protein concentration on the breaking force and distance were evaluated and compared utilizing response surface methodology. Models for breaking force and breaking distance of grass carp surimi were established. Protein concentration was the major factor affecting the gel strength of grass carp surimi. Breaking force and distance of grass carp surimi gels decreased with increase of protein ratio from SPI at 30 °C and 40 °C for 60 min setting and heating at 85 °C for 30 min, but the breaking force obtained for addition of 100 g kg^?1 SPI protein to grass carp surimi was higher than that for surimi alone at 60 °C for 60 min incubation and heating at 85 °C for 30 min. Copyright © 2005 Society of Chemical Industry     

Serotonin‐transporter promoter polymorphism modulates the ability to control food intake: Effect on total weight loss

Scope

The biggest challenge for losing weight is the ability to control the amount of food eaten; the tendency to overeat is called disinhibition. Our aims were to determine whether (a) the SLC6A 4‐promoter variant (5‐HTTLPR) relates to disinhibition; (b) this association could affect total weight‐loss during a behavioral/dietary treatment for obesity.

Methods and results

A total of 2961 subjects attended voluntarily five weight‐loss clinics; a subsample (n = 624) was recruited for SLC6A4 genotyping. Total weight‐loss, emotional‐eating‐score and disinhibition‐score were examined. We observed that: (a) the reduced ability to control food intake (disinhibition) is implicated in the impairment to lose weight; (b) SLC6A 4‐promoter variant is implicated in disinhibition. S carriers (low‐expressing) of the SLC6A4‐promoter variant had a lower inhibition capacity and showed more failure (1.6 times) to control the amount of food eaten than LL (p < 0.05); other factors such as eating while bored, overeating after work at night, or craving for specific foods were associated to the SLC6A4 genotype (p < 0.05); (c) The combination of disinhibition (high disinhibition) and genetics (S carrier) had a higher impact on total weight loss than each factor separately.

Conclusions

SLC6A 4‐promoter variant is associated with the ability to control food intake and interacts with emotional eating to modulate total weight loss.

     

Developing treatment protocols for disinfesting pine wood product using radio frequency energy

Numerous non-native insect pests are moved around the world via international trade and have caused major forestry losses, especially for pine trees. The purpose of this research was to study a potential application of radio frequency (RF) heating for disinfesting pine wood products to reduce forestry damage caused by exotic pests. A pilot-scale 6 kW, 27.12 MHz RF system was used to develop a treatment protocol for disinfesting pine wood products based on the heating uniformity studies. The results showed that the heating time needed was only 6.7 min to heat the wood blocks (250?×?400?×?60 mm³) with moisture content of 13.3% d.b. from 25 to 60?°C using RF energy, but 320 min to reach 56.2?°C using hot air at 60?°C with 1.6 m/s. Based on the heating uniformity study, the best condition occurred when the lower wood moisture content was used and the wood width approached the RF electrode one. The RF treatment protocol was finally developed to combine RF energy with forced hot air at 60?°C, movement of conveyor at 7.4 m/h and holding at 60?°C hot air for 1 min. Wood quality was not affected significantly by the RF treatments because quality parameters of treated wood samples were similar to those of controls. The RF treatment may provide a rapid, effective and environmentally friendly method to disinfest wood products.     

Effect of gelation factors on the formation and characteristics of protease‐induced whey protein gel

Whey protein gel formed at 10% (w/v) whey protein concentration, 0.5% E/S, pH 7.0, 55°C and 2.5 mM CaCl₂ concentration had an average particle size of 23.46 μm, hardness of 0.46, cohesiveness of 0.13 and adhesiveness of 1.40, and the gel showed semisolid, smooth and creamy texture. There were no distinct changes in gel textural properties after heating at 80 and 90°C for 5 min, respectively, or being kept at 4°C for 1 month. The textural properties of the gel showed no significant difference after its pH was adjusted to 4.5, 5.5 and 7.5 compared with that of pH 6.5 (control gel). However, the average particle size significantly increased after being adjusted to pH 4.5 and pH 5.5. Transmission electron micrographs showed that protease‐induced gel possessed much looser aggregate structure compared with heat‐induced compact gel, which may give support to its potential application in low‐fat foods that no need of extensive heating.     

l‐Citrulline Supplementation‐Increased Skeletal Muscle PGC‐1α Expression Is Associated with Exercise Performance and Increased Skeletal Muscle Weight

Scope

l ‐citrulline has recently been reported as a more effective supplement for promoting intracellular nitric oxide (NO) production compared to l ‐arginine. Here, the effect of l ‐citrulline on skeletal muscle and its influence on exercise performance were investigated. The underlying mechanism of its effect, specifically on the expression of skeletal muscle peroxisome proliferator‐activated receptor‐gamma coactivator‐1α (PGC‐1α), was also elucidated.

Methods and results

Six‐week‐old ICR mice were orally supplemented with l ‐citrulline (250 mg kg^?1) daily, and their performance in weight‐loaded swimming exercise every other day for 15 days, was evaluated. In addition, mice muscles were weighed and evaluated for the expression of PGC‐1α and PGC‐1α‐regulated genes. Mice orally supplemented with l ‐citrulline had significantly higher gastrocnemius and biceps femoris muscle mass. Although not statistically significant, l ‐citrulline prolonged the swimming time to exhaustion. PGC‐1α upregulation was associated with vascular endothelial growth factor α (VEGFα) and insulin‐like growth factor 1 (IGF‐1) upregulation. VEGFα and IGF‐1 are important for angiogenesis and muscle growth, respectively, and are regulated by PGC‐1α. Treatment with NG‐nitro‐l ‐arginine methyl ester hydrochloride (l ‐NAME), a nitric oxide synthesis inhibitor, suppressed the l ‐citrulline‐induced PGC‐1α upregulation in vitro.

Conclusion

Supplementation with l ‐citrulline upregulates skeletal muscle PGC‐1α levels resulting in higher skeletal muscle weight that improves time to exhaustion during exercise.

     

Non-enzymatic Depolymerization of Carrot Pectin: Toward a Better Understanding of Carrot Texture During Thermal Processing

ABSTRACT Pretreated carrot discs were thermally processed (90 °C to 110 °C) in closed containers and the resulting textural characteristics were analyzed. The pretreatment conditions used include conventional high‐temperature blanching (90 °C, 4 min), low‐temperature blanching (LTB = 60 °C, 40 min), LTB combined with 0.5% calcium chloride soaking, LTB combined with 2% sodium chloride soaking, high pressure pretreatment (HP = 400 MPa, 60 °C, 15 min), HP combined with 0.5% calcium chloride soaking, and control (non‐pretreated sample). Alcohol insoluble residues (AIR) from the pretreated carrot discs were characterized in terms of degree of methoxylation (DM). The AIR samples were further subjected to fractionation into water‐soluble pectin (WSP), chelator‐soluble pectin (CSP), and sodium carbonate‐soluble pectin (NSP). Heat depolymerization patterns and β‐elimination kinetics were investigated on the different pectin fractions. Thermal texture degradation was strongly influenced by the pretreatment condition used and the processing temperature during subsequent thermal treatment. Pretreatment conditions that showed a significant reduction in DM exhibited decreased WSP content, reduced β‐elimination, and consequently superior textural characteristics. β‐elimination was markedly pronounced in the highly methoxylated WSP fractions. CSP and NSP fractions were insensitive to β‐elimination. A strong correlation (r> 0.95) between thermal texture loss of carrots and β‐elimination kinetics exists. Overall, the benefits of controlled pectinmethylesterase activity in carrot processing were pointed out.