Kinetics of Ascorbic Acid Degradation in Green Asparagus during Heat Processing

The effect of heating on ascorbic acid in green asparagus during a simulated retort operation was investigated. The asparagus was heated in trays of ethylene-vinyl alcohol copolymer for selected time intervals at four temperatures ranging from 110 to 125 degrees C. It was found that the rate of degradation followed first-order kinetics. Kinetic parameters were obtained by using two least squares methods. The activation energy and z value were 35 kcal/mol and 20 degrees C, respectively.

Influence of pulsed electric field processing on the quality of fruit juice beverages sweetened with Stevia rebaudiana

Abstract A fruit juice-stevia beverage was processed using pulsed electric fields (PEF), a non-thermal preservation technology, with the purpose of investigating the feasibility of PEF for bioactive compounds and steviol glycosides enhancement and its impact on physicochemical properties. Variable ranges of response surface methodology were 20–40 kV/cm (electric field strength), 100–360 μs (treatment time) and 0–2.5% (w/v) stevia. After PEF, ascorbic acid was retained by more than 74%. Some of the analyzed PEF treatments resulted in an enhancement of total anthocyanins and carotenoids. The best results for rebaudioside A/stevioside ratio were obtained when PEF was applied at 30 kV/cm for 23…

Food Allergy Knowledge, Attitudes and Practices: A Pilot Study of the General Public and Food Handlers

Objective: We have assessed the factors that might improve the free food allergen at the restaurants. In addition, we have compared food handlers knowledge with the general public knowledge about food allergens. Design: Cross-sectional, via questionnaires. Participants: A total of 182 participants (80 food handlers and 102 of general public). Main Outcome Measures: Dependent variables: Food allergy knowledge, attitudes and practices. Analysis: The analysis of variance (ANOVA) and independent t-test. Questionnaires were hand coded and data was analyzed using Statistical Package for Social Sciences (SPSS) version 19.0. Results: The survey showed that food handlers and general public had some …

Dietary Assesment of Free-Living Elderly Spanish People with Disabilities.

Nutritional research in elderly disabled is difficult in noninstitutionalized people. The dietary intake of a noninstitutionalized disabled population of the eastern region of Spain was evaluated to detect possible nutritional deviations. A total of 329 participants aged 65 and over were recruited. Most participants were overweight. Carbohydrates did not reach 50% of total Kcal/day. Insufficient micronutrient intakes and high consumption of simple carbohydrates and saturated fats (SFA) were found. A decreasing trend of water intake (p < .05) as well as an increasing trend of alcohol consumption (p < .05) with increasing age was found. The area of residence had a relevant impact on nutrition…

Comparison of voltammetric and high performance liquid chromatographic methods for ascorbic acid determination in infant formulas

Abstract Two methods — voltammetric and high performance liquid Chromatographic (HPLC) — useful for determining ascorbic acid in foods, were compared to ascertain which of them could be used for routine determination of ascorbic acid in infant formulas. Both methods were used to assay 10 identical samples of an adapted cow's milk infant formula and 10 samples of soya protein formula. Precision was determined, the variance of each method was measured, and the methods were compared with each other. The variances of the two methods were not statistically different nor was there any significant difference between the results from the two methods. Therefore, it was concluded that both methods ca…

Determination of ascorbic acid in asparagus by differential pulse polarography

A useful method for the determination of ascorbic acid in a vegetable product (asparagus) by differential pulse polarography has been set up and evaluated. Extraction and instrumental conditions were optimized. The analytical parameters are: linearity (0–18.18 μg/ml); detection limit (0.182 μg/ml); instrumental and method precision (2.77% and 4%, respectively); accuracy (96.9–113.4%). These data show that the method is sufficiently sensitive, reliable and accurate. It was also compared with the official fluorometric AOAC method.

Quality characteristics of horchata (a Spanish vegetable beverage) treated with pulsed electric fields during shelf-life

Abstract The application of pulsed electric fields (PEF) is one of the new non-thermal technologies being studied to evaluate their potential as alternative or complementary processes to thermal pasteurization. “Horchata de chufa” (tiger nut milk or earth almond milk) is of high nutritional quality and therefore has great potential in the food market, limited by its very short shelf-life. The present work studies whether PEF can be used to obtain a quality horchata and increase its shelf-life while maintaining its organoleptic characteristics. In order to do so we determined pH, total fat, peroxide index, thiobarbituric acid-reactive substances index, formol index, and peroxidase activity i…

Carotenoids and Color of Fruit Juice and Milk Beverage Mixtures

Seventeen commercially available, "ready to drink" fortified beverages consisting of mixtures of fruit juices and milk were analyzed to evaluate their carotenoid profile (including their Z/E stereoisomers) and color during their commercial shelf life. Lightness (L*) was found to be correlated with the content of milk in the mixtures (r= 0.649) whereas red-yellow colors were correlated with the contents of alpha-carotene, beta-cryptoxanthin, and beta-carotene supplied by the fruit. The beverages stored under refrigeration (4 +/- 2 degrees C) showed higher luminosity (L*) and higher saturation of color (C*) and yellowness (b*). Differences (P < 0.05) in the levels of carotenoids were found am…

Use of polarography as a quality-control method for determining diacetyl in citrus and vegetable juices, yoghurt and butter

The determination of diacetyl permits the detection of microbial growth in the processing of citrus fruit before the appearance of other organoleptic, chemical or microbiological changes. It also makes it possible to detect a break in the cold chain during distribution and sale. The study proposed a polarographic method for the determination of diacetyl that allowed routine analysis with the aim of detecting possible contamination in the citrus juice manufacturing chain (orange and orange-carrot). The analytical performance of the method in terms of a linearity from 0 to 960 microg ml(-1), a recovery of 97 to 98%, a precision of 3.2 to 4.8%, and a sensitivity of 0.2 ng ml(-1) for juices ind…

Antioxidant capacity of cow milk, whey and deproteinized milk

The total antioxidant capacity (hydrophilic plus lipophilic) of sixteen different commercial samples of pasteurized and ultra high temperature (UHT) treated milk was determined using the oxygen radical absorbance capacity assay using fluorescein as a fluorescent probe. A significant correlation between the percentage of fat and the value of the total antioxidant capacity was found in milk samples obtained from the same batch of raw milk. Analyses of the whole milk, whey and deproteinized milk showed that the major contributor to the total antioxidant capacity of whole milk was the casein fractions, while albumin was the major contributor to the total antioxidant capacity of whey protein. Hy…

Ascorbic acid stability during refrigerated storage of orange–carrot juice treated by high pulsed electric field and comparison with pasteurized juice

Abstract The degradation kinetics of ascorbic acid was determined in orange–carrot juice treated by PEF in order to establish its shelf life. Different electric field intensities (25, 30, 35, and 40 kV/cm) and different treatment times (from 30 to 340 μs) were studied. The ascorbic acid degradation rate (k) obtained was −0.009 ± 0.0008 μs−1, −0.0140 ± 0.0009 μs−1, −0.0220 ± 0.0023 μs−1 and −0.0187 ± 0.0049 μs−1 for fields of 25, 30, 35, and 40 kV/cm, respectively. The treatment selected was 25 kV/cm. The shelf life of the orange–carrot juice treated by pulses at 25 kV/cm for two times (280 μs and 330 μs) was compared with a heat-treated juice (98 °C, 21 s) kept in refrigerated storage at 2 …

Steviol Glycosides Stability after Pulsed Electric Technologies and Ultrasounds Treatments in Fruit Juice Blend Sweetened with Stevia rebaudiana

Stevia rebaudiana bartoni due to its high content in steviol glycosides and the ability to serve as a natural antimicrobial to complement the effectiveness of pulsed electric technologies for food preservation, has been used more frequently to improve sensorial properties of liquid foods.

Effect of traditional, microwave and industrial cooking on inositol phosphate content in beans, chickpeas and lentils

An high-performance liquid chromatography method for determining inositol phosphate fractions was adapted to legumes. The validity of the method was assessed by estimating the following analytical parameters: linearity (linear response between 125 and 5000 microg inositol hexaphosphate (IP(6))/ml); instrumental precision and method precision (relative standard deviation, %) were 1.9% (IP(6)) for instrumental, and 2.5% (IP(6)) and 8.2% (IP(5)) for method precision. An accuracy was estimated by percentage recovery (72 +/- 3%). The application of this method to raw, conventional, microwave-cooked and ready-to-eat beans, chickpeas and lentils gave IP(6) contents ranging from 0.63 g/100 g dry ma…

Determination of Cd, Cu, Pb and Zn content of infant formulas by differential pulse anodic stripping voltammetry (DPASV).

The differential pulse anodic stripping voltammetry (DPASV) method described is based on the one reported by Hasse et al., but adapted to normal laboratory conditions. The values obtained in the estimation of the analytical parameters (linearity, detection and quantification limits, precision and accuracy) show that in the conditions described the method is sensitive enough, reliable and useful for determining these elements in infant formulas. A comparison between DPASV and atomic absorption spectroscopy (AAS) methods in the conditions described here shows that the former is less sensitive but that they are similar in precision. The cadmium, copper, lead and zinc contents of different type…

Dimensions of household food waste focused on family and consumers

Food waste produced in homes represents the largest fraction of food waste generated along the food chain. Therefore, adequate prevention measures based on the quantitative and qualitative dimensions of the problem need to be put in place to reduce waste. The objective of the review was to identify areas of interest in relation to the food waste in households, considering the family unit as a whole as well as individual family members. Quantifying the problem is an important aspect in order to know its scope and dimension, but prevention also involves knowing the causes in a home. This is a complex issue, which, on a family level, is related to socioeconomic status, educational level, compo…

Simultaneous Determination of Thiamin and Riboflavin in Mushrooms by Liquid Chromatography

A simple, fast, inexpensive, and reliable method useful for the simultaneous, routine determination of thiamin and riboflavin in mushrooms is examined. It uses the extraction procedure, with slight modifications, proposed by the AOAC for the extraction of thiamin and riboflavin, followed by a liquid chromatographic separation on a reversed-phase Spherisorb ODS column with methanol/water as mobile phase gradient. Fluorometric detection is used at the following excitation and emission wavelengths, respectively, 360 and 425 nm in the case of thiamin and 422 and 515 nm for riboflavin. The analytical parameters of linearity, the precision of the method (RSD = 2.45 and 2.51% for thiamin and ribof…

The effects of non-thermal processing on carotenoids in orange juice

New non-thermal technologies are emerging, such as pulsed electric fields (PEF) and high hydrostatic pressure (HHP), in order to provide a response to the need for greater nutritional and sensory quality in some manufactured foods in which the characteristics of freshness are especially affected by thermal treatments. The effect of non-ther - mal processing (PEF, 30 kV/cm, 100 µs and HHP, 4000 bars, 5 min) and pasteurisation (90°C, 20 s) on carotenoids of orange juice was studied. The total carotenoid concentration in the pasteurised juice (1195.4 ± 31.6 µg/100 ml) decreased significantly in comparison with the fresh juice (1367.2 ± 64.7 µ g/100 ml), and the decrease was less in the juice t…

Kinetics of green asparagus ascorbic acid heated in a high-temperature thermoresistometer

Thermal degradation of green asparagus ascorbic acid in high-temperature short-time conditions was studied by heating in a five-channel computer-controlled thermoresistometer. Ascorbic acid was heated to between 110  °C and 140  °C and the degradation kinetics were analyzed assuming that two different inactivation mechanisms were occurring, one aerobic and the other anaerobic. The two reactions followed first-order kinetics, with E a=12.3(2.0) kcal/mol and k 125  °C=47.0(3.0)×10–3 s–1 for the aerobic oxidation, and E a=6.1(1.4) kcal/mol and k 125  °C=4.1(0.2)×10–3 s–1 for the anaerobic degradation.

Effect of storage period under variable conditions on the chemical and physical composition and colour of Spanish refrigerated orange juices

The effects of the physicochemical and quality characteristics of various minimally pasteurized refrigerated orange Spanish juices and their changes with storage time and temperature were investigated. Essential oils, acidity, conductivity, diacetyl index, hydroxymethylfurfural, formol index, viscosity and ascorbic acid varied with storage time more significantly at 10 degrees C than at 4 degrees C. Density, colour and pectinmethylesterase did not vary at 4 degrees C. Some of the parameters could be used as indicators of quality loss or spoilage of the juices. The degradation kinetics of the concentration of remaining ascorbic acid against time follows a straight line whose slope indicates …

Ascorbic acid degradation kinetics in mushrooms in a high-temperature short-time process controlled by a thermoresistometer

Abstract The degradation of ascorbic acid was studied in mushrooms heated at temperatures between 110 and 140°C, high-temperature short-time conditions, in a five-channel computer-controlled thermoresistometer. The kinetics parameters were calculated on the assumption that there are 2 degradation mechanisms, one aerobic (during the first few seconds of the process) and the other anaerobic. The 2 stages followed first-order reaction kinetics, with E a =46.36 kJ/mol for aerobic degradation and E a =49.57 kJ/mol for anaerobic degradation.

Contents of vitamins B1, B2, B6, and B12 in pork and meat products

The concentration of B vitamins (B(1), B(2), B(6), and B(12)) was determined in three pork muscles (Longissimus dorsi, loin; Biceps femoris, ham; and Triceps brachii, shoulder) and in pork and other meat products (cooked, pickled, and cured), of importance because they are consumed in high quantities. The results were compared with values reported by other authors and their contribution to the daily intake of these vitamins estimated. This showed that pork provides, on average, 97, 25.8, 35/43.7 (men/women), and 37% of the RDA (Recommended Dietary Allowances) for vitamins B(1), B(2), B(6), and B(12), respectively.

Anteroxanthin concentration during refrigerated storage in orange juice treated by PEF

Pulsed Electric Field (PEF) processing inactivates microorganisms without significant adverse effects on flavor and nutrients. In this work was studied the transformations of antheraxanthin and mutatoxanthin when natural orange juice is treated by pasteurisation (90°C, 20 s) or PEF (30 kV/cm, 100 µs), and also its evolution during seven weeks of storage in refrigeration at two different temperatures (2°C and 10°C). The results showed that antheraxanthin concentration decreased during the storage. The decrease was greater in the untreated, pasteurised and PEF-treated orange juices stored at 10°C and this carotenoid was not detected from the 6 th week onwards. The same result was observed in …

Identification and quantification of carotenoids including geometrical isomers in fruit and vegetable juices by liquid chromatography with ultraviolet-diode array detection.

A method was established for the identification and quantification of carotenoids including geometrical isomers in fruit and vegetable juices by liquid chromatography with an ultraviolet−diode array detector, using a C18 Vydac 201TP54 column. The mobile phase used was the ternary methanol mixture (0.1 M ammonium acetate), tert-butyl methyl ether and water, in a concentration gradient, and a temperature gradient was applied. Retinol palmitate was added as an internal standard. An extraction process (ethanol/hexane, 4:3, v/v) was performed, followed by saponification with diethyl ether/methanolic KOH (0.1%, w/v, BHT) (1:1, v/v) for 0.5 h at room temperature. Seventeen different (cis and trans…

Changes of colour and carotenoids contents during high intensity pulsed electric field treatment in orange juices

Abstract Liquid chromatography (LC) was the method chosen to evaluate the effects of high intensity pulsed electric fields (HIPEF), with different electric field intensities (25, 30, 35 and 40 kV/cm) and different treatment times (30–340 μs), on orange juice cis / trans carotenoid contents. In parallel, a conventional heat treatment (90 °C, 20 s) was applied to the orange juice in order to compare the effect on the carotenoid contents. HIPEF processing of orange juice is an alternative to the thermal treatment of pasteurization, provided that it is kept refrigerated, because, when the most extreme conditions of this kind of treatment are applied, the decrease in the concentration of caroten…

Study of consumer perception of healthy menus at restaurants

Abstract To improve food-away-from-home nutritional quality, not only must healthy food options be available but also consumers must respond by making those choices. However, this is not always possible, as consumers believe healthy foods are loss tasty. A new concept of gastronomy focused not only on sensations but also on nutrition and health is necessary. The aim of this research is to evaluate whether offering a healthy menu based on nutritional claims would be an interesting option for restaurants as well as to check the impact of proposed nutritional improvements on consumer’s acceptability of menus. 300 customers of a specific restaurant located in Valencia city center (Spain) partic…

Determination of liposoluble vitamins in cooked meals, milk and milk products by liquid chromatography

A method for the simultaneous determination of liposoluble vitamins in cooked meals was established. Saponification was performed with 50% (w/v) KOH at 80 degrees C, and ascorbic acid was added as antioxidant. The subsequent extraction was carried out with diethyl ether. This was followed by a liquid chromatographic separation on a reversed-phase C18 column with methanol-water (94:6, v/v as the mobile phase. Retinyl acetate was used as the internal standard. The analytical parameters linearity, detection limit (0.19 and 8.33 microg/100 g for retinol and alpha-tocopherol, respectively), precision of the method (RSD=5.24 and 6.99% for retinol and alpha-tocopherol, respectively) and recovery a…

Total antioxidant capacity of refrigerated orange juice treated with pulsed electric fields

Pulsed Electric Field Processing Optimization of Ascorbic Acid in a Mango and Papaya Beverage Sweetened with Stevia Rebaudiana

During the processing of liquid foods, ascorbic acid may be altered, thus reducing beneficial health effects. For this reason, the degradation kinetics of ascorbic acid were determined in a fruit juice mixture (papaya and mango) sweetened with Stevia rebaudiana (SR) infusion after treatment by pulsed electric field (PEF) processing. The variable ranges were 20-40 kV/cm (electric field strength, E) during 100-360 μs (time treatment, t). The degradation equation was AA (mg/100 mL) = 26.842 - 0.101·E - 0.003·t- 10.371·%Stevia + 2.865·%Stevia2, demonstrating the use of PEF as an alternative to pasteurization treatments. However, results show the need to optimize treatment conditions whenever th…