Yerba mate tea (Ilex paraguariensis): Phenolics,antioxidant capacity and in vitro inhibition of colon cancer cell proliferation

Mate tea (MT) is a rich source of phenolic compounds that vary depending on geographical origin and mode of preparation. Total phenolic concentration and antioxidant capacity of Mate tea (Ilex paraguariensis) products were determined in this work. In addition, a representative MT was tested for in vitro inhibition of human colon carcinoma cell proliferation. Total polyphenol concentration, was measured using Folin–Ciocalteau method, ranged from 90 to 176 mg gallic acid eq (GAE)/g dry leaves (DL) in traditional MT and from 40 to 113 mg GAE/g DL in MT added with other flavouring ingredients. It was estimated that a cup of tea (250 ml) containing one teaspoon (5 g) of instant MT could provide an average intake of 1.5 g GAE. Fresh tea (FT) from Mate leaves displayed high antioxidant capacity (85 ± 1%) and preferentially inhibited 50% of net growth of human colorectal adenocarcinoma cells CaCo-2 (GI₅₀ = 1.0 ± 0.03 μg/ml) and HT-29 (GI₅₀ = 105.2 ± 15.2 μg/ml) when compared with the CCD-33Co normal colon fibroblast cell line (GI₅₀ > 300 μg/ml). MT inhibited in vitro colon cancer cell proliferation possibly mediated via pro-oxidant activities, therefore represents a potential source of chemopreventive agents that deserve further investigation.     

Development of QuEChERS-based extraction and liquid chromatography–tandem mass spectrometry method for quantifying flumethasone residues in beef muscle

A rapid, specific, and sensitive method based on liquid chromatography–electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS) in the positive ion mode using multiple reaction monitoring (MRM) was developed and validated to quantify flumethasone residues in beef muscle. Methods were compared between the original as well as the EN quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction. Good linearity was achieved at concentration levels of 5–30 μg/kg. Estimated recovery rates at spiking levels of 5 and 10 μg/kg ranged from 72.1 to 84.6%, with relative standard deviations (RSDs) < 7%. The results of the inter-day study, which was performed by fortifying beef muscle samples (n = 18) on 3 separate days, showed an accuracy of 93.4–94.4%. The precision (expressed as relative standard deviation values) for the inter-day variation at two levels of fortification (10 and 20 μg/kg) was 1.9–5.2%. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.7 and 5 μg/kg, at signal-to-noise ratios (S/Ns) of 3 and 10, respectively. The method was successfully applied to analyze real samples obtained from large markets throughout the Korean Peninsula. The method proved to be sensitive and reliable and, thus, rendered an appropriate means for residue analysis studies.     

Tea and herbal infusions: Their antioxidant activity and phenolic profile

Tea and herbal infusions have been studied for their polyphenolic content, antioxidant activity and phenolic profile. The total phenolics recovered by ethyl acetate from the water extract, were determined by the Folin–Ciocalteu procedure and ranged from 88.1 ± 0.42 (Greek mountain tea) to 1216 ± 32.0 mg (Chinese green tea) GAE (Gallic acid equivalents)/cup. The antioxidant activity was evaluated by two methods, DPPH and chemiluminescence assays, using Trolox and quercetin as standards. The EC₅₀ of herbal extracts ranged from 0.151 ± 0.002 mg extract/mg DPPH (0.38 quercetin equivalents and 0.57 Trolox equivalents), for Chinese green tea, to 0.77 ± 0.012 mg extract/mg DPPH (0.08 quercetin equivalents and 0.13 Trolox equivalents), for Greek mountain tea. Chemiluminescence assay results showed that the IC₅₀ ranged from 0.17 ± 3.4 × 10⁻³ μg extract/ml of the final solution in the measuring cell (1.89 quercetin and 5.89 Trolox equivalents) for Chinese green tea, to 1.10 ± 1.86 × 10⁻² g extract/ml of the final solution in the measuring cell (0.29 quercetin and 0.90 Trolox equivalents) for Greek mountain tea. The phenolic profile in the herbal infusions was investigated by LC-DAD-MS in the positive electrospray ionization (ESI⁺) mode. About 60 different flavonoids, phenolic acids and their derivatives have been identified.     

Angiotensin I-converting enzyme inhibitory activity of chickpea and pea protein hydrolysates

ACE inhibitory activity was studied for different hydrolysates obtained from protein concentrates of chickpea (kabuli and desi) and yellow pea (Golden) using in vitro gastrointestinal simulation, alcalase/flavourzyme, and papain. Protein/peptide profiles studied by SDS–PAGE and SE-HPLC, showed a rich composition of the hydrolysates in small peptides having MWs under 4 kDa. Papain hydrolysed yellow pea proteins showed the highest ACE inhibitory activity. In addition, chickpea desi proteins hydrolysed by in vitro gastrointestinal simulation showed higher ACE inhibition (IC₅₀ of 140 ± 1 μg/ml) compared to its digests obtained by alcalase/flavourzyme (IC₅₀ of 228 ± 3 μg/ml) or papain (IC₅₀ of 180 ± 1 μg/ml) and to chickpea kabuli hydrolysed by gastrointestinal simulation (IC₅₀ of 229 ± 1 μg/ml). The results demonstrate that enzymatic hydrolysates of chickpea and pea proteins contain bioactive ACE inhibitory peptides; furthermore, the type of enzyme used for hydrolysis affects the ACE inhibitory activity.     

Availability of essential elements in Indian and US tea brands

Fifteen different brands of Indian tea leaves and seven US brands of flavoured tea were analysed for Na, K, Mn, Cu and Br by thermal neutron activation analysis (TNAA). Mn was also analysed by spectrophotometric and atomic absorption spectrometry (AAS) methods. In Indian tea, Mn concentration was found to be in the range 371–758 μg/g with a mean concentration of 575 ± 96 μg/g whereas in US tea it was in the range 79–768 μg/g with a mean concentration of 329 ± 231 μg/g. Na and Cu contents were also widely different in tea leaves from India and the USA but K contents were similar in the two tea leaves. Bromine was absent in tea leaves from the USA. Several standard or certified reference materials (SRMs/CRMs), including two tea leaves standards, were also analysed for data validation.     

Relationship between photon emission and chemopreventive potential of tea

Photon emission from tea (610–670 nm) in the H₂O₂/KHCO₃/MeCHO system and the utility of the photon detection system in tea evaluation were investigated. Photon intensity of tea depended on manufacturing method as follows: green tea (1202 ± SD 173.51 cd/m²) > oolong tea (834 ± SD 237.44 cd/m²) > black tea (222 ± SD 87.65 cd/m²). Photon intensity corresponded with polyphenol content (r²=0.8810) rather than catechin content (r²=0.7759) and showed a high correlation with chemopreventive activities against H₂O₂ (r²=0.7516), O₂⁻ (r²=0.7998) and DPPH radical (r²=0.7516). Photon intensity from green tea leaves at each manufacturing process step gave the same decreasing curve as DPPH radical scavenging activity. Chemiluminescence of tea, which gives information on the polyphenol content and chemopreventive potential, is a useful technique for tea evaluation.     

Consumption of highly processed foods: Effects on bioavailability and status of zinc and copper in adolescents

The effects of consuming diets with different Maillard reaction products (MRP) content on zinc and copper bioavailability and status were examined. In a 2-week randomised 2-period crossover trial, 18 male adolescents consumed two diets, named white diet (WD) and brown diet (BD), which were poor and rich in MRP, respectively. A 3-day balance was performed at the end of each period and fasting blood samples were collected. Zinc bioavailability did not vary significantly between the diets (%WD: 21.0 ± 5.0, %BD: 15.1 ± 5.1), but BD consumption increased copper faecal excretion (~ 1.8-fold) and significantly decreased its bioavailability (~ 3.0-fold). Biochemical parameters related to zinc metabolism remained unaltered whereas copper in serum and erythrocytes significantly decreased after consumption of the BD (72.47 ± 2.42 μg/dl and 0.93 ± 0.01 μg/ml in serum and erythrocytes with WD compared to 65.87 ± 3.11 μg/dl and 0.84 ±0.02 μg/ml with BD). The present results suggest that the high presence of MRP in the diet does not affect zinc but negatively affects copper bioavailability. As both minerals are essential trace elements involved in adolescents' growth and development, possible long-term effects of excessive MRP intake during adolescence warrant attention.     

Mate tea-mediated reduction in catecholamine synthesis improves cutaneous wound healing of chronically stressed mice

Chronic stress stimulates oxidant production and oxidative damage which compromise cutaneous wound healing. Mate tea rich is in antioxidant compounds and may be a good alternative for treatment of oxidative diseases. Therefore, the aim of this study was to investigate the effects of supplementation with mate tea on cutaneous healing in stressed mice. Mice were submitted to rotational stress (ST) and treated with mate tea (MT) daily until euthanasia. An excisional lesion was created on each mouse and 4 or 10 days later, the lesions were analyzed. In addition, murine skin fibroblasts were exposed to elevated epinephrine (E) levels plus mate tea, and fibroblast activity was evaluated. In in vivo assays, the supplementation with mate tea inhibited the stress-induced increase in: catecholamine synthesis (ST: 23.3 ± 2.5; ST + MT: 18.0 ± 0.9 ng/μl, p < 0.05), carbonyl protein content (ST: 962.0 ± 35.6; ST + MT: 35.7 ± 8.9 nmol/μg protein, p < 0.05), lipid peroxide levels (ST: 18.5 ± 2.3; ST + MT: 11.8 ± 1.2 nmol/mg protein, p < 0.05), wound contraction (ST: 44 ± 4; ST + MT: 17 ± 2%, p < 0.05), re-epithelialization (ST: 908 ± 35; ST + MT: 2081 ± 138 μm, p < 0.05), transforming growth factor-β (ST: 5.0 ± 0.02; ST + MT: 1.3 ± 0.06 u.a., p < 0.05), and myofibroblast density (ST: 19 ± 2; ST + MT: 9 ± 1%, p < 0.05). Stress-induced reduction in the amount of macrophages (ST: 133 ± 19; ST + MT: 392 ± 33 cells, p < 0.05) and neutrophils (ST: 1161 ± 62; ST + MT: 1313 ± 103 cells, p < 0.05) and hydroxyproline levels (ST: 1.3 ± 0.2; ST + MT: 4.6 ± 0.9 ng/mg tissue, p < 0.05), and this was reversed by mate tea. In in vitro assays, the treatment with mate tea reversed the reduction in collagen deposition (E: 1.7 ± 0.3; E + MT: 3.7 ± 0.01 pixels, p < 0.05) and the increase in cell proliferation (E: 331 ± 2; E + MT: 203 ± 3% of control, p < 0.05), accumulation of lipid peroxides (E: 0.66 ± 0.009; E + MT: 0.55 ± 0.01 nmol/mg protein, p < 0.05), and increase of tenascin-C protein expression (E: 3.8 ± 0.004; E + MT: 3.4 ± 0.004 a.u., p < 0.05) induced by epinephrine. In conclusion, the supplementation with mate tea improves the cutaneous wound healing of chronically stressed mice.     

Purification and characterization of angiotensin I-converting enzyme inhibitory peptides of small red bean (Phaseolus vulgaris) hydrolysates

Angiotensin I-converting enzyme (ACE) inhibitory activity was investigated for small red bean (Phaseolus vulgaris) protein hydrolysate produced by sequential digestion of Alcalase, papain followed by in vitro gastrointestinal simulation. The hydrolysate had ACE inhibitory activity with IC₅₀ of 67.2 ± 1.8 μg protein/mL. Peptides responsible for potent ACE inhibitory activity were isolated by a three-step purification process, including ultrafiltration, gel filtration and preparative reverse phase high performance chromatography (RP-HPLC). The fraction obtained after RP-HPLC fractionation with the highest activity yielded an IC₅₀ of 19.3 ± 1.4 μg protein/mL. Enzymatic kinetic studies using this fraction demonstrated competitive inhibition with K_i of 11.6 ± 1.7 μg protein/mL. Mass spectrometric characterization identified for the first time the octapeptide PVNNPQIH which demonstrated an IC₅₀ value of 206.7 ± 3.9 μM. The results expand the knowledge base of ACE inhibitory properties of small red bean protein hydrolysate and should be useful in further identification of specific ACE inhibitory peptides in beans.     

Phospholipids determination in vegetable oil by thin-layer chromatography and imaging densitometry

A rapid reliable method was developed to measure vegetable oil phospholipid content by thin-layer chromatography–imaging densitometry. Phospholipid samples were obtained from crude soybean oil by water degumming and then analyzed and quantified by thin-layer chromatography and imaging densitometry. Phosphatidyl choline (PC), phosphatidyl ethanolamine (PE) and phosphatidyl inositol (PI) standard curves were generated. The total phospholipid content of the oil was 1.12–1.26%, of which 27.1 ± 1.86% was PC, 22.7 ± 0.45% was PE, while PI accounted for 17.2 ± 0.85% of the total. A high correlation coefficient of 0.985 was found for reproducibility of pixel area (OD*mm) at a constant concentration of standard phospholipid. Regression analysis of the pixel area vs the phospholipid (PC, PE, and PI) weights (μg) generated R² greater than 0.983. Thin-layer chromatography–imaging densitometry proved a useful tool for rapid determination and quantification of the major phospholipids in soybean oil.     

Evaluation of Chemical Properties of Mistletoe Leaves from Three Different Trees (Avocado,African Oil Bean and Kola)

A comparative evaluation of the chemical composition of mistletoe leaves (Viscum album) growing on three different trees: avocado pear (Persea Americana), African oil bean (Pentaclethra macrophylla) and kola (Kola nitida) was undertaken. Fresh mistletoe leaves were obtained from the three different trees and thoroughly washed with water after which they were dried at room temperature (28 ± 1 °C) for 18 days during the dry season (December). After, the dried leaves were shredded and packaged. The samples were then subjected to phyto-chemical, vitamin and mineral analyses using standard methods of analyses. Anthocyanins ranged between 0.3.4 ± 0.003 and 0.37 ± 0.181 mg/g, Tannin, 2.09 ± 1.141 and 3.24 ± 0.003 mg/g, Chlorophyll a, 0.38 ± 0.004 and 0.39 ± 0.018 mg/g, Chlorophyll b 0.52 ± 0.120 and 0.60 ± 0.001 mg/g. Vitamin B1 ranged between 0.85 ± 0.038 and 0.94 ± 0.001 mg/g, Vitamin B2, 0.55 ± 0.007 and 0.61 ± 0.003 mg/g, Vitamin C, 0.77 ± 0.003 and 1.98 ± 0.003 mg/g, Folate 0.53 ± 0.004 and 0.58 ± 0.004 mg/g, Magnesium ranged between 0.21 ± 0.002 and 0.92 ± 0.003 mg/g, Calcium 2.14 ± 0.004 and 2.26 ± 0.001 mg/g, Sodium 0.01 ± 0.000. Iron, 1.24 ± 0.005 and 1.42 ± 0.006 mg/g. Sample obtained from oil bean tree showed lower and differed significantly (p < 0.05) in Anthocyanin and Chlorophyll b with samples obtained from avocado and kola trees. The sample obtained from avocado tree showed higher Tannin content compared with samples obtained from oil bean and kola trees (P ≤ 0.05). There were significant differences (P < 0.05) between the samples in all the vitamins. The minerals showed significant differences in the samples (P < 0.05) except in sodium content which was very low in all the samples. Mistletoe leaves are shown to have a rich chemical composition and could thus serve as a source of these phyto-chemicals, vitamins and minerals.     

Behaviour of soyasapogenol B under optimised hydrolysis and ESI mass spec conditions

Soyasaponins are oleanane triterpenoids found in soy (Glycine max Merr). The analysis of the main aglycone (soyasapogenol B) is hampered by inconsistent ion fragmentation patterns produced during MS analysis. The greatest (p < 0.05) increase in soyasapogenol B during acid hydrolysis HCl (5% (v/v)) was at 100 °C (84.59 ± 4.73 μg/ml), followed by 120 °C (69.82 ± 6.20 μg/ml) and 80 °C (46.54 ± 6.41 μg/ml). The capillary temperature (LC–ESI-MS) of 220 °C produced the greatest (p < 0.05) intensity of soyasapogenol B ion. Temperatures between 200 and 250 °C consisted the optimum temperature range for analysing soyasapogenol B. At low capillary temperatures (<200 °C), the soyasapogenol B ion ([M?H]^? = 457.4) was converted to an ion m/z at 441, while, at temperatures ?250 °C the soyasapogenol B ion produced ions m/z at 440 and 437. We report an analysis procedure for detecting intact soyasapogenol B molecular ion without the typical fragmentation reported in the literature.     

Effect of process unit operations and long-term storage on catechin contents in EGCG-enriched tea drink

Due to the increasing market for functional foods and the chemopreventive action of (?)-epigallocatechin gallate (EGCG), manufacturers produce ready-to-drink green tea infusions enriched or not in EGCG. However, the maintenance of green tea catechins stability in drinks is always a challenge. In this context, the objectives of this study were (1) to assess the catechin stability in tea drink during a 6-month storage, (2) to evaluate the impact of process unit operations on catechin stability and (3) to compare the catechin and caffeine contents of commercially available tea drinks. It appeared that the stability of catechins during long-term storage was optimum at low temperature (4 °C) and acidic pH (pH 4.0). During the processing of the EGCG-enriched green tea drink, all the process unit operations, except heat-treatment, had no impact on catechin concentrations. In addition, in commercially available tea drinks, except enriched green tea drinks, their catechin contents are very low to provide health benefits.     

Effects of baking and aging on the changes of phenolic and volatile compounds in the preparation of old Tieguanyin oolong teas

A series of old oolong teas was prepared by baking fresh Tieguanyin oolong teas at 120–140 °C for 72 h, followed by a long-term storage of 5, 10 and 20 years. To monitor the chemical changes of the tea preparation, phenolic and volatile compounds in a fresh or its newly baked tea were analyzed and compared with those in the three aged teas. The contents of phenolic compounds in the teas were apparently altered by the baking, but remained relatively stable thereafter in the aging process. The contents of major catechin derivatives and flavonol glycosides presumably responsible for astringency and bitterness of teas were reduced while those of gallic acid and gallocatechin gallate, putatively originated from the decomposition and isomerization of (−)-epigallocatechin gallate, were elevated after baking. In contrast, linear and branched hydrocarbons, the abundant volatile compounds in the fresh tea, were relatively stable in the baking process, but nearly diminished during the long-term storage. Relatively minor contents of substituted benzaldehydes and pyrrole derivatives probably rendering the unique flavor of old oolong teas were generated after the baking and aging processes.     

Tea fluoride concentration and the pediatric patient

The purpose of this study was to measure the fluoride concentrations of various commercially available tea infusions, with a specific focus on risk of fluorosis. 100 ml infusions of 43 different tea brands were kept at a constant temperature of 85 °C and measured for fluoride concentration at 5, 15, 30, 60, and 120 min using a fluoride ion-specific electrode and millivolt meter. After 5 min at 85 °C mean fluoride concentration, in μg/ml with standard deviation, was 2.08 ± 1.24 for caffeinated tea infusions, 4.38 ± 0.97 for decaffeinated tea infusions, and 0.05 ± 0.02 for herbal teas. Caffeinated teas derived from the traditional source, Camellia sinensis, demonstrated significantly higher concentrations of fluoride than herbal teas (p < 0.01). Furthermore, decaffeinated teas demonstrated significantly higher concentrations of fluoride than caffeinated teas (p < 0.01). Some tea infusions may place a pediatric patient at higher risk for fluorosis if consumed as the primary source of hydration.     

Formulation with ascorbic acid and sucrose modulates catechin bioavailability from green tea

In order to investigate the impact of common food ingredients on catechin absorption, green tea (GT) extract (50 mg) was formulated plain, with sucrose (GT + S), with ascorbic acid (GT + AA) and with sucrose and ascorbic acid (GT + S + AA). Bioavailability and bioaccessibility were assessed in Sprague Dawley rats and an in vitro digestion/Caco-2 cell model respectively. Absorption of epigallocatechin (EGC) and epigallocatechin gallate (EGCG) was significantly (P < 0.05) enhanced in GT + S + AA formulations (AUC_0–6 h = 3237.0 and 181.8 pmol h/L plasma respectively) relative to GT control (AUC_0–6 h = 1304.1 and 61.0 pmol h/L plasma respectively). In vitro digestive recovery was higher for EGC and epicatechin (EC) (～51–53%) relative to EGCG and epicatechin gallate (ECG) (<20%) and was modestly enhanced in GT + S and GT + S + AA formulations. Accumulation of EGC, EGCG and ECG by Caco-2 cells was significantly (P < 0.05) higher from GT + S + AA compared to other formulations while retention of catechins was enhanced in presence of ascorbic acid. These data suggest that formulation with sucrose and ascorbic acid may improve catechin bioavailability by enhancing bioaccessibility and intestinal uptake from tea.     

Changes in central corneal thickness values after instillation of oxybuprocaine hydrochloride 0.4%

PurposeTo assess the variation in central corneal thickness (CCT) following the instillation of oxybuprocaine hydrochloride (0.4%), in normal subjects.MethodsThis was a randomized, prospective study of CCT measurements (before and after the instillation of topical anaesthesia) obtained with the Topcon SP-3000P noncontact specular microscope, in 60 eyes of thirty subjects. The subjects’ mean age was 20 ± 1 years (mean ± SD). In each subject, one eye was treated with one drop of oxybuprocaine hydrochloride (HCl) and the fellow eye with one drop of normal saline (control). The SP-3000P CCT readings were first obtained before instillation (baseline) and monitored every 30 s after instillation of each eye drop for a period of 10 min.ResultsThe mean baseline CCT for oxybuprocaine was 526 ± 23 μm. Ten minutes after, it was 526 ± 24 μm. In the control, the mean CCT was 526 ± 27 μm, 10 min after it was 526 ± 28 μm. The mean variation in CCT measurement was ?0.7 ± 3.1 (5.5 to ?6.8 μm, 95% CI) for oxybuprocaine and ?0.6 ± 4.1 μm (7.5 and ?8.6 μm, 95% CI) for the fellow eyes (P > 0.05). There was no significant variation among the 20 CCT columns for either oxybuprocaine or the control group (P > 0.05 for both).ConclusionsOne drop of topical oxybuprocaine 0.4% did not cause a significant change in CCT at up to 10 min following instillation. However, higher differences were observed at 2.30 min and 4.30 min after instillation.     

Carotenoid content,its stability during drying and the antioxidant activity of commercial coriander (Coriandrum sativum L.) varieties

Although populations of several tropical countries are under severe vitamin-A deficiency, traditional sources of pro-vitamin-A carotenoids have not been exploited due to the lack of relevant research data. In this study, ten commercial varieties of coriander (Coriandrum sativum L.), grown at identical conditions, were evaluated for carotenoids, their bio-efficacy and stability during drying, with the main emphasis on β-carotene (vitamin-A precursor) analysis by HPLC-MS. In all varieties, β-carotene content was higher in foliage at mature stage, than in seedlings and seeds. Variety GS4 Multicut produced highest biomass (6.18 ± 0.73 g/plant), total carotenoids (217.50 ± 5.6 mg/100 g DW) and β-carotene (73.64 ± 0.3 mg/100 g DW) at pre-flowering stage. Carotenoids extract showed a high antioxidant activity with IC₅₀ value of 14.29 ± 1.68 μg/ml, scavenging hydroxyl radicals and rendering higher protection to DNA than by standard gallic acid (IC₅₀ = 357.21 ± 4.29). Microwave drying of foliage was rapid with better retention of pigments, high intactness of trans-β-carotene and higher extractability of pigments when compared with oven drying.     

Differences in the glucose-induced insulin response and the peripheral insulin responsiveness between neonatal calves of the Belgian Blue,Holstein-Friesian,and East Flemish breeds

Decreased insulin sensitivity (IS) in dairy cows supports milk yield but increases the risk for metabolic and reproductive disorders. Although several inducers of decreased IS are known, it is unclear to what extent it is congenitally determined. The main aim was to investigate differences in IS between neonatal calves of the Belgian Blue (BB) breed, reared for beef production, and the Holstein-Friesian (HF) breed, reared for milk yield. Additionally, a small number of East Flemish (EF) calves, a local dual-purpose breed, were compared with the 2 other breeds. Ten BB, 12 HF, and 4 EF calves with similar age, ration, and housing were selected. In the intravenous glucose tolerance test, blood samples were taken at regular intervals after an intravenous glucose bolus of 150 mg/kg. Area under the curve (AUC), peak concentration, and elimination rate of insulin and glucose were computed. The quantitative insulin sensitivity check index (QUICKI) and revised QUICKI were computed using basal glucose, insulin, and nonesterified fatty acid concentrations. In the intravenous insulin tolerance test, blood samples were obtained from 4 calves of each breed at regular times after an intravenous insulin challenge of 0.05 IU/kg. Based on the decline in glucose concentrations relative to basal levels, the insulin-stimulated blood glucose response was computed. Basal insulin concentrations were higher in HF (1.58 ± 0.40 μU/mL) than in BB calves (0.35 ± 0.09 mmol/L). Compared with BB calves, HF and EF calves had higher basal glucose concentrations (4.40 ± 0.16 vs. 5.70 ± 0.35 and 5.81 ± 0.13 mmol/L, respectively), insulin peak concentrations (4.62 ± 1.09 vs. 9.70 ± 1.45 and 16.44 ± 5.58 μU/mL, respectively), insulin AUC (86.71 ± 18.81 vs. 222.65 ± 45.00 and 293.69 ± 109.22 μU/mL·min, respectively), and glucose AUC (256.22 ± 17.53 vs. 335.66 ± 18.74 and 321.03 ± 10.05 mmol/L·min, respectively). Glucose elimination rates were lower in HF (1.37 ± 0.22%/min) than in BB calves (2.35 ± 0.25%/min). The QUICKI was lower in HF and EF than in BB calves (0.52 ± 0.039 and 0.57 ± 0.068 vs. 0.76 ± 0.038, respectively), and the revised QUICKI was lower in HF (0.86 ± 0.11) than in BB calves (1.59 ± 0.17). The insulin-stimulated blood glucose response did not differ between breeds. Because management differences were negligible, our results suggest breed-specific differences in glucose partitioning and IS. These findings may reflect different rearing purposes of the breeds, although extrapolation of the data to adult animals should be done cautiously.     

Effect of ohmic heating on texture,microbial load,and cadmium and lead content of Chilean blue mussel (Mytilus chilensis)

The effect of ohmic heating (OH) on the texture, microbial load, and cadmium (Cd) and lead (Pb) content was evaluated in Chilean blue mussel (Mytilus chilensis) at shucking and subsequent canning. Mussel samples were processed by OH and blanching (BLAN) at 50 ± 1 °C, 70 ± 1 °C and 90 ± 1 °C for shucking and then canning at 115 °C for 20 min. The Cd and Pb content in fresh mussels was 2.47 ± 0.18 μg g^− 1 and 5.26 ± 0.55 μg g^− 1 dry weight (dw). The greatest reduction in Cd content was reached at 90 ± 1 °C by OH with 1.67 ± 0.06 μg g^− 1 (dw) and 1.69 ± 0.08 μg g^− 1 (dw) by BLAN. At the same temperature, the Pb content was reduced to 4.18 ± 0.24 μg g^− 1 dw for OH and 4.14 ± 0.30 μg g^− 1 dw for BLAN. The cutting strength of fresh samples (21.35 ± 2.44 N) significantly decreased in samples processed by OH (15.65 ± 1.36 N) at 90 ± 1 °C compared with BLAN samples (20.41 ± 3.16 N) at the same temperature. The initial mean count for mesophilic aerobic microorganisms and Enterobacteriaceae was 3.8 log cfu/g and 2.5 log cfu/g, respectively. The mesophilic aerobic microorganism count was reduced by 1.7 logarithmical units, while Enterobacteriaceae counts were reduced to undetectable levels by OH at 90 ± 1 °C.Industrial relevanceHigh temperature short time (HTST) processes rely on rapid convection heat transfer and are thus well suited to liquid foods. But, they are, however, limited in application to particulates since, for particles more than a couple of millimeters thick, the processing time is insufficient for heat to transfer to the center to give sterility. Ohmic heating is an emerging technology and very promising in food industries. It is a thermal process in which heat is generated internally in food and acts as a resistance to the flow of alternating electric current. This type of treatment prevents overheating by producing less deterioration in food components. It is a rapid procedure that allows food to conserve its natural properties; microorganisms and enzymes are also inactivated. The purpose of the present work was to evaluate the effect of Ohmic heating on mechanical properties, microbial load, Cd and Pb content in the opening and subsequent canning of Chilean blue mussel (Mytilus chilensis). This information could be used for the seafood industries in order to improve thermal heating processes in mussels.