The effect of irradiation temperature on the quality improvement of Kimchi,Korean fermented vegetables,for its shelf stability

The present study was conducted to evaluate the effect of irradiation temperature on the shelf stability and quality of Kimchi during storage at 35 °C for 30 days. Kimchi samples were N₂-packaged and heated at 60 °C and then gamma irradiated at 20 kGy under various temperatures (room temperature, ice, dry ice, and liquid nitrogen). In the results of microbial, pH, and acidity analysis, combination treatment of heating and irradiation was able to sterilize microbes in Kimchi regardless of irradiation temperature. When Kimchi was irradiated under frozen temperatures, especially dry ice, the softening of texture and the deterioration of sensory quality of Kimchi were reduced. Also, ESR signal intensities were weakened due to the decrease of irradiation dose and temperature.     

Effects of gamma irradiation on chemical,microbial quality and shelf life of shrimp

In the present study the combined effect of gamma irradiation (1, 3 and 5 kGy) and storage at two temperatures: refrigeration (+4 °C) and frozen (?18 °C), on the shelf-life extension of fresh shrimp meat was investigated. The study was based on microbiological and physicochemical changes occuring in the shrimp samples. Total volatile base nitrogen values and trimethylamine values for irradiated shrimp samples were significantly lower than non-irradiated samples at both storage temperatures, and the rate of decrease was more pronounced in samples irradiated at the higher dose (p<0.05). Thiobarbituric acid values for irradiated shrimp samples were significantly higher than non-irradiated samples at both storage temperatures (p<0.05). pH values of shrimp samples were affected significantly by both irradiating dose and storage temperatures (p<0.05). Microbial counts for non-irradiated shrimp samples were higher than the respective irradiated samples at both storage temperatures (p<0.05). The results revealed that irradiation at high dose (5 kGy) might enhance lipid oxidation, although the growth of microorganisms and protein oxidation was inhibited.     

A fast isocratic liquid chromatography method for the quantification of xanthophylls and their stereoisomers

A fast isocratic liquid chromatography method was developed for the simultaneous quantification of eight xanthophylls (13‐Z‐lutein, 13’‐Z‐lutein, 13‐Z‐zeaxanthin, all‐E‐lutein, all‐E‐zeaxanthin, all‐E‐canthaxanthin, all‐E‐β‐apo‐8’‐carotenoic acid ethyl ester and all‐E‐β‐apo‐8’‐carotenal) within 12 min, compared to 90 min by the conventional high‐performance liquid chromatography method. The separation was achieved on a YMC C₃₀ reversed‐phase column (100 mm x 2.0 mm; 3 μm) operated at 20°C using a methanol/tert‐butyl methyl ether/water solvent system at a flow rate of 0.8 mL/min. The method was successfully applied to quantify lutein and zeaxanthin stereoisomers in egg yolk, raw and cooked spinach, and a dietary supplement. The method can be used for the rapid analysis of xanthophyll isomers in different food products and for quality control purposes.     

Glycated hemoglobin (HbA1c) measurement in frozen whole blood depends on baseline values of fresh samples

Glycated hemoglobin (HbA1c) has been recently adopted as a diagnostic marker of type 2 diabetes. However, its usage is currently limited to fresh blood samples. To allow retrospective HbA1c measurement in blood banks developed in large epidemic studies, here, we contribute to validate HbA1c assessment in frozen versus fresh blood samples from a cohort of diabetic/nondiabetic adult subjects. HbA1c was measured by HPLC in 237 fresh whole blood samples and on the same samples after a 12-month storage and a further 6-month-refrozen storage. Mean HbA1c?±?SD in fresh, frozen, and refrozen samples was 6.9?±?1.2, 6.6?±?1.1, and 6.4?±?1.0 % for the Diabetes Control and Complications Trial and 52?±?13, 49?±?12, and 46?±?11 mmol/mol for the International Federation of Clinical Chemistry and Laboratory Medicine reference, respectively. A significant correlation was found between fresh/frozen and fresh/refrozen (R?=?0.994 and 0.993, P?<?0.001) samples. HbA1c relative error ratio (%RER) between frozen/refrozen and fresh samples significantly correlated with HbA1c and depended on fresh value range, increasing in the five HbA1c classes (<6.0, 6.0–6.5, 6.5–7, 7–8, ≥8 %, corresponding to <42, 42–48, 48–53, 53–64, ≥64 mmol/mol, P?<?0.001). In particular, the 6.5 % (48 mmol/mol) HbA1c diagnostic cutoff of fresh samples identified two classes reflecting significant differences in %RER (2.8?±?2.0 and 3.3?±?1.7; P?<?0.05) between frozen and fresh samples. In conclusion, our results demonstrate a high correlation between data from fresh and frozen samples, with a very limited %RER between the two measurements, which increases with baseline HbA1c levels. Accordingly, when analyzing biobank frozen specimens for diagnostic purpose, the effect of the HbA1c range should be taken into account.

Gamma irradiation of sun-dried apricots (Prunus armeniaca L.) for quality maintenance and quarantine purposes

The study is aimed at the optimization of gamma irradiation treatment of sun-dried apricots for quality maintenance and quarantine purposes. Sun-dried apricots pre-treated with potassium meta-bisulphite (KMS) at 2.5% w/v were procured from progressive apricot grower of district Kargil, Ladakh region of Jammu and Kashmir state. The sun-dried apricots were packed in 250 gauge polyethylene packs and gamma irradiated in the dose range 1.0–3.0 kGy. The gamma irradiated fruit including control was stored under ambient (15±2–25±2 °C, RH 70–80%) conditions and periodically evaluated for physico-chemical, sensory and microbial quality parameters. Radiation treatment at dose levels of 2.5 and 3.0 kGy proved significantly (p≤0.05) beneficial in retention of higher levels of β-carotene, ascorbic acid, total sugars and color values without impairing the taste as perceived by the sensory panel analysists. The above optimized doses retained the β-carotene content of sun-dried apricots to the extent of 71.2% and 72.6% compared to 63.9% in control samples after 18 months of storage. Irradiation treatment facilitated the release of residual sulfur dioxide in KMS pre-treated sun-dried apricots significantly (p≤0.05) below the prescribed limit for dried products. During storage, two-fold decrease in sulfur dioxide content was recorded in irradiated samples (3.0 kGy) as compared to 16.9% in control. The above optimized doses besides maintaining the higher overall acceptability of sun-dried apricots resulted in 5 log reductions in microbial load just after irradiation and 1.0 and 1.3 log reductions in yeast and mold and bacterial count after 18 months of ambient storage.     

Zeaxanthin Production by Novel Marine Isolates from Coastal sand of India and its Antioxidant Properties

Zeaxanthin carotenoids are class of commercially important natural products and diverse biomolecules produced by plants and many microorganisms. Bacteria often produce a cocktail of polar and nonpolar carotenoids limiting their industrial applications. Marine members of the family Flavobacteriaceae are known to produce potential carotenoids such as astaxanthin and zeaxanthin. A few bacterial species have been reported for the predominant production zeaxanthin. Here, we report the molecular identification of the zeaxanthin as a major carotenoid produced by two novel bacteria (YUAB-SO-11 and YUAB-SO-45) isolated from sandy beaches of South West Coast of India and the effect of carbon sources on the production of zeaxanthin. The strains were identified based on the 16S rRNA gene sequencing as a member of genus Muricauda. The closest relatives of YUAB-SO-11 and YUAB-SO-45 were Muricauda aquimarina (JCM 11811^T) (98.9 %) and Muricauda olearia (JCM 15563^T) (99.2 %), respectively, indicating that both of these strains might represent a novel species. The highest level of zeaxanthin production was achieved (YUAB-SO-11, 1.20?±?0.11 mg g^?1) and (YUAB-SO-45, 1.02?±?0.13 mg g^?1) when cultivated in marine broth supplemented with 2 % NaCl (pH 7) and incubated at 30 °C. Addition of 0.1 M glutamic acid, an intermediate of citric acid cycle, enhanced the zeaxanthin production as 18 and 14 % by the strains YUAB-SO-11 and YUAB-SO-45 respectively. The zeaxanthin showed in vitro nitric oxide scavenging, inhibition of lipid peroxidation, and 2,2-diphenyl-1-picryl hydrazyl scavenging activities higher than the commercial zeaxanthin. The results of this study suggest that two novel strains YUAB-SO-11 and YUAB-SO-45 belonging to genus Muricauda produce zeaxanthin as a predominant carotenoid, and higher production of zeaxanthin was achieved on glutamic acid supplementation. The pigment showed good in vitro antioxidant activity, which can be exploited further for commercial applications.     

An improved method of simultaneous determination of lutein and zeaxanthin in food

Based on an official standard method of lutein analysis, an improved high performance liquid chromatography (HPLC) method for simultaneously detecting lutein and zeaxanthin was developed as focusing on the sample preparation protocol. The optimal pretreatment conditions included a saponification in a water bath for 15?min at a constant temperature of 50?°C, using a 10?mL 60% (w/v) potassium hydroxide solution, followed by extraction using 100?mL mixture of n-hexane, ethyl ether and cyclohexane (40: 40: 20, v/v/v). A mixture of dichloromethane, acetonitrile and methanol (20: 30: 50, v/v/v) was validated to elute lutein and zeaxanthin on a C₃₀ column (4.6?×?250?mm, 5?µm). The resolution between lutein and zeaxanthin is ≥2.5. A millet sample was used for methodological verification and the results showed that the linear relations for lutein and zeaxanthin were good in ranges of 0.23–9.37?μg/mL and 0.30–12.02?μg/mL, respectively. The relative standard deviations of lutein and zeaxanthin were 1.40% and 5.09%, respectively, and their spiked recoveries were between 86.60% and 98.75%. The lutein and zeaxanthin results from this modified HPLC method are superior to those from the Chinese official method and ultrasonic extraction method.     

Degradation of amisulbrom and its metabolite IT-4 in cucumber under field conditions and processing

The study of the pesticide degradation and residue change is a global challenge during open field growing and processing of agricultural products. In this study, the degradation of a new fungicide, amisulbrom and its metabolite IT-4 in cucumber during field growing, home processing and storage was assessed. A combination method of modified QuEChERS and high performance liquid chromatography-tandem mass spectrometry with average recoveries of 86.3–107.1% and relative standard deviations of 2.9–7.0% was proposed to measure the concentrations of the two compounds in cucumber samples. The half-lives of amisulbrom under field condition were 4.5–5.8 days and the terminal residues ranged from 0.010 mg/kg to 0.11 mg/kg. Results from processing studies showed that gradual reduction of amisulbrom with 5.5–50.9% was presented with the increased operation time and temperature of washing or cooking. There was an obvious loss of 7.3–14.5% for amisulbrom from cucumber when stored at 4°C in dark for 120 h, and 5.8–37.7% reduction of amisulbrom stored at 25°C, respectively, whereas no significant loss of amisulbrom was observed in cucumber samples stored at ?20°C. The degradation of reduced amisulbrom residues to IT-4 was only found in cucumber samples during cooking with the concentrations of 0.0011–0.018 mg/kg. All of the processing factors were below 1 indicating these processing procedures could eliminate amisulbrom levels. This work is useful for evaluating degradation of amisulbrom and IT-4 in raw and processed cucumber, and also providing guidance to develop an effective approach for removing pesticide residues from commodities.     

LC Method for Quantification of Lutein in Rat Plasma: Validation, and Application to a Pharmacokinetic Study

A reversed-phase LC method has been developed for quantitative analysis of lutein in rat plasma and applied to a study of the pharmacokinetics of lutein in rats. From a variety of compounds and solvents tested, astaxanthin was selected as the internal standard. n-Hexane was found to be the best solvent for extracting lutein from plasma. LC analysis of the extracts was performed on a C₁₈ column equipped with a guard pre-column. Linearity was good (r > 0.99) over the range 10–100 ng mL^?1. Recovery from plasma was 82.7–92.9% the intra-day and inter-day precision were always better than 3%. The limits of detection (LOD) and quantification (LOQ) were 2.5 and 8.3 ng mL^?1, respectively. The LC method was used to quantify lutein and zeaxanthin in rat plasma in a 36-h pharmacokinetic study in which experimental rats received a single oral dose of lutein (20 mg kg^?1). The results are presented.     

Optimization of clean extraction methods to isolate carotenoids from the microalga Neochloris oleoabundans and subsequent chemical characterization using liquid chromatography tandem mass spectrometry

A novel experimental design was used to optimize the extraction of carotenoids from Neochloris oleoabundans using pressurized liquid extraction with food-grade solvents such as ethanol and limonene. Experimental factors, including the extraction temperature and the solvent composition, were optimized using a three-level factorial design. The response variables extraction yield and total amount of carotenoids were assessed. The statistical analysis of the results provided mathematical models to predict the behavior of the responses as a function of the factors involved in the process. The optimum conditions predicted by the model developed in this study were 112 °C as the extraction temperature and 100 % ethanol as the extraction solvent. Chemical characterization of the extracts obtained was performed by means of high-performance liquid chromatography–tandem mass spectrometry. The results obtained demonstrated that, under certain growth conditions (photoautotrophically cultured in a medium supplemented with 0.3 g?L^?1 KNO₃), N. oleoabundans accumulated significant total amounts of the carotenoids (from 57.4 to 120.2 mg carotenoids per gram of extract depending on the extraction conditions), mainly lutein, cantaxanthin, zeaxanthin, and astaxanthin monoesters and diesters.     

Preparation and applicability of fresh fruit samples for the identification of radiation treatment by EPR

The results of electron paramagnetic resonance (EPR) study on fresh fruits (whole pulp of pears, apples, peaches, apricots, avocado, kiwi and mango) before and after gamma-irradiation are reported using two drying procedures before EPR investigation. In order to remove water from non-irradiated and irradiated samples of the first batch, the pulp of fresh fruits is pressed, and the solid residue is washed with alcohol and dried at room temperature. The fruits of the second batch are pressed and dried in a standard laboratory oven at 40 °C. The results obtained with both drying procedures are compared. All samples under study show a singlet EPR line with g=2.0048±0.0005 before irradiation. Irradiation gives rise to typical “cellulose-like” EPR spectrum featuring one intensive line with g=2.0048±0.0005 and two very weak satellite lines situated 3 mT at left and right of the central line. Only mango samples show a singlet line after irradiation. The fading kinetics of radiation-induced EPR signal is studied for a period of 50 days after irradiation. When the irradiated fruit samples are stored in their natural state and dried just before each EPR measurement, the satellite lines are measurable for less than 17 days of storage. Irradiated fruit samples, when stored dried, lose for 50 days ca. 40% of their radiation-induced radicals if treated with alcohol or ca. 70% if dried in an oven. The reported results unambiguously show that the presence of the satellite lines in the EPR spectra could be used for identification of radiation processing of fresh fruits, thus extending the validity of European Protocol EN 1787 (2000). Foodstuffs—Detection of Irradiated Food Containing Cellulose by EPR Spectroscopy. European Committee for Standardisation. Brussels for dry herbs.     

Thermal analysis of contemporary glass-ionomer restorative materials

The thermal characteristics of four conventional glass-ionomer cement (GIC) dental restorative products as well as five resin-modified glass-ionomer (RMGI) materials over 1-year of storage were investigated. All materials were prepared following manufacturer’s recommendations and placed into 40 μL aluminum differential scanning calorimeter (DSC) crucibles. Samples (n = 5) were stored at 37 °C and 98 ± 2 % humidity until their appointed time of evaluation at which they were first subjected to specific heat analysis using DSC over 20–60 °C that was immediately followed by a 37–600 °C thermal scan at 10 °C min^?1. Samples were evaluated immediately after preparation, at 24 h, 1 week, 1 month, as well as at 3, 6, 9, and 12 months. Mean thermal results were compared with analysis of variance and Scheffe post-hoc testing (p = 0.05). All materials absorbed water during storage. Conventional GIC materials demonstrated increased polyalkenoate polymer maturity over the 12-month storage. The paste–paste RMGI materials, absorbed more water during storage and had increased specific heat values compared to powder–liquid RMGI materials. Of the RMGI materials investigated, only two materials demonstrated evidence of a continuing polyalkenoate matrix maturity that was within the limitations of the technology used, indicating the resin component in some newer formulations of RMGI restorative materials may severely limit the polyalkenoate reaction.     

Effects of deep-freezing and storage time on human femoral cartilage

Surgical techniques including new, possible resources to repair injured joints and damaged cartilage are still evolving. The exact effects of cryopreservation on the collected cartilage samples require accurate determination prior to utilization. The aim of our study was to analyze the impact of cryopreservation at ?80 °C on the structural properties of the human cartilage. The effects of storage time were also evaluated in conjunction with optimal utilization. The human cartilage samples were derived during operation and considered to be waste material. Samples were fresh frozen and stored at ?80 °C. Cryopreservation times were: 0, 1, 3, 6, and 12 weeks. To assess the biological and structural properties of the frozen human cartilage, we performed calorimetric examinations using differential scanning calorimetry (DSC). During the first 3 weeks, the calorimetric enthalpy (ΔH _cal) showed an increasing tendency compared to controls, parallel with the denaturation temperature (T _m): ΔH _cal (J g^?1) = 1.60 versus 2.49, T _m1 (°C) = 61.73 versus 63.64. After the sixth week, both the enthalpy and the transition temperature decreased, compared to the control samples. The decrease in both the calorimetric enthalpy and T _m could be explained by the decrease in bound water and the time-related degeneration in the structure of the cartilage. Here we found that the duration of cryopreservation interferes with the morphology of human cartilage samples only after 6 weeks of storage time. The thermal analyzes of human cartilage by DSC could be a useful method to follow the morphological changes in the clinical practice.     

Gamma radiolytic degradation of the endrin insecticide in methanol and monitoring of radiolytic degradation products by HPLC

The objective of this investigation was to verify the degradation of endrin by gamma irradiation. ⁶⁰Co was used as radiation source for irradiation of 50 mg L^?1 endrin with a varied dose of 1–6 kGy. High performance liquid chromatography (HPLC) coupled with diode array detector was used as an analytical technique to monitor the degradation rate along with numbers of degradation products formed. At dose rate of 6 kGy ≥99% of endrin was degraded. It is proposed that utilization of ionization radiations can be an effective and efficient tool for the removal of halogenated pesticides.     

Combined effect of gamma irradiation and hot water dipping on the selected nutrients and shelf life of peach

Gamma irradiation in combination with hot water dipping treatment was tested for maintaining storage quality and extending the shelf life of peach fruit. The matured peaches fruits (local variety no, Tex-A-6-69) were first dipped in hot water having temperature of 0, 40 and 60 °C for 60 seconds and they were exposed to 0.5 and 1.0 kGy doses of gamma radiation and stored in paper cartons under ambient (temperature 25 ± 2 °C, RH 70 %) conditions for their physico-chemical evaluations on weekly basis. The combine effect of hot water dipping treatment and irradiation for peach was study for the first time in Pakistan. The parameters studied included % weight loss, % ash content, % moisture content, total soluble solids (TSS), titratable acidity and ascorbic acid. The sensory indices studied were size, shape, color and overall acceptability. The sensory evaluation values at 0 days for the controlled peach sample were recorded for comparison. Statistical analysis was performed to find determinates of irradiation alone and in combination with hot water dipping techniques on peaches. Studies revealed that irradiation treatment in combination with hot water treatments significantly (LSD at 5 %) maintained the storage quality of peach fruit under ambient conditions. Data obtained for weight loss, moisture, shape and overall acceptability showed significant results while non-significant values were recorded for ash, TSS and size. Overall, consumers rated the acceptability of treated peaches higher than untreated peaches. This particular type of research also helps in improving one’s country export quality of fruits.     

Influence of gamma irradiation and storage on the microbial load,chemical and sensory quality of chicken kabab

Influence of gamma irradiation and storage on the microbial load, chemical and sensory quality of chicken kabab was investigated. Chicken kabab was treated with 0, 2, 4 or 6 kGy doses of gamma irradiation. Treated and untreated samples were kept in a refrigerator (1–4 °C). Microbiological, chemical and sensory characteristics of chicken kabab were evaluated at 0–5 months of storage. Gamma irradiation decreased the microbial load and increased the shelf-life of chicken kabab. Irradiation did not influence the major constituents of chicken kabab (moisture, protein and fats). No significant differences (p>0.05) were observed for total acidity between non-irradiated (control) and irradiated chicken kabab. Thiobarbitric acid (TBA) values (expressed as mg malonaldehyde (MDA)/kg chicken kabab) and volatile basic nitrogen (VBN) in chicken kabab were not affected by the irradiation. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples.     

In vitro stability of free and glucuronidated cannabinoids in urine following controlled smoked cannabis

Analyte stability is an important factor in urine test interpretation, yet cannabinoid stability data are limited. A comprehensive study of Δ⁹-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol, cannabinol, THC-glucuronide, and THCCOOH-glucuronide stabilities in authentic urine was completed. Urine samples after ad libitum cannabis smoking were pooled to prepare low and high pools for each study participant; baseline concentrations were measured within 24 h at room temperature (RT), 4 °C and -20 °C. Stability at RT, 4 °C and ?20 °C was evaluated by Friedman tests for up to 1 year. THCCOOH, THC-glucuronide, and THCCOOH-glucuronide were quantified in baseline pools. RT THCCOOH baseline concentrations were significantly higher than ?20 °C, but not 4 °C baseline concentrations. After 1 week at RT, THCCOOH increased, THCCOOH-glucuronide decreased, but THC-glucuronide was unchanged. In RT low pool, total THCCOOH (THCCOOH?+?THCCOOH-glucuronide) was significantly lower after 1 week. At 4 °C, THCCOOH was stable 2 weeks, THCCOOH-glucuronide 1 month and THC-glucuronide for at least 6 months. THCCOOH was stable frozen for 1 year, but 6 months high pool results were significantly higher than baseline; THC-glucuronide and THCCOOH-glucuronide were stable for 6 months. Total THCCOOH was stable 6 months at 4 °C, and frozen 6 months (low) and 1 year (high). THC, cannabidiol and cannabinol were never detected in urine; although not detected initially, 11-OH-THC was detected in 2 low and 3 high pools after 1 week at RT. Substantial THCCOOH-glucuronide deconjugation was observed at RT and 4 °C. Analysis should be conducted within 3 months if non-hydrolyzed THCCOOH or THCCOOH-glucuronide quantification is required.

Analysis of SMELS by k 0-based IM-NAA method using PFTS position of KAMINI reactor for quality control exercise

As a part of QA/QC of k ₀-based internal monostandard neutron activation analysis (IM-NAA), three types of synthetic multielement standards (SMELS) were analyzed using pneumatic fast transfer system irradiation position of KAMINI reactor, IGCAR. Radioactive assay of activation products was carried out by high resolution gamma ray spectrometry. IM-NAA was used to determine relative concentration ratios of 22 elements with respect to gold internal monostandard. Absolute concentrations were calculated using assigned concentration of Au in all the types of SMELS. Z-score values within ±1 at 95.5 % confidence level and percentage deviations within ±5 % indicated good quality of the results by IM-NAA in most of the cases. Using this methodology, an ilmenite mineral sample was analyzed and concentrations of 14 elements were determined using Sc as monostandard.     

Investigation of <Emphasis Type="Italic">Chlorella vulgaris</Emphasis> UTEX 265 Cultivation under Light and Low Temperature Stressed Conditions for Lutein Production in Flasks and the Coiled Tree Photo-Bioreactor (CTPBR)

Lutein has an increasing share in the pharmaceutical and nutraceutical market due to its benefits to eye health. Microalgae may be a potential source for lutein production while the expense limits the commercialization. In this study, a coiled tubular tree photobioreactor (CTPBR) design was investigated for cultivating the cold tolerant microalgae Chlorella vulgaris UTEX 265 under various conditions for lutein production. The influence and interaction of light irradiance strength, lighting cycle, and temperature on microalgae and lutein production efficiency at low temperature range were also studied in flasks via response surface method (RSM). The results demonstrated that 14 h day-light, 120 μmol photons m^?2 s^?1, and 10 °C was the optimal condition for algae growth and lutein production at low temperature experimental ranges. C. vulgaris UTEX 265 showed good potential to produce lutein in cold weather, and the optimum lutein production was contrary to the specific lutein content but corresponds to the trend of optimum growth. Additionally, fast growth (μ = 1.50 day^?1) and good lutein recovery (11.98 mg g^?1 day^?1) in CTPBR were also achieved at the low irradiance stress condition and the low temperature photo-inhibition conditions.