Comparison of digestion methods for determination of trace and minor metals in plant samples

In this paper, three dissolution methods using pressure digestion vessels (low-, medium-, and high-pressure vessels) for the determination of metals in plant samples are described. The Plackett-Burman saturated factorial design was used to identify the significant factors influencing wet ashing and to select optimized dissolution conditions. The three methods were statistically compared (on-way ANOVA) on the same sample; no significant differences were obtained. In all cases the relative standard deviation values were <3%. The digestion method based on the use of low-pressure vessels and a microwave oven was validated against CRM GBW07605 tea leaves. This method was applied to the determination of Cu, Zn, Mn, Fe, Mg, and Ca in 22 different medicinal, aromatic, and seasoning plants by flame-atomic absorption spectrometry. The concentration intervals of metal in the plants analyzed were the following: Cu, 4 (Allium sativum)-35 (Thea sinensis) microg g(-1); Zn, 7 (Piper nigrum)-90 (Betula alba) microg g(-1); Mn, 9 (Allium sativum)-939 (Caryophylus aromaticus) microg g(-1); Fe, 33 (Allium sativum)-2486 (Anethum graveolens) microg g(-1); Mg, 495 (Allium sativum)-7458 (Ocimum basilicum) microg g(-1); Ca, 386 (Allium sativum)-21500 (Ocimum basilicum) microg g(-1).     

Depth Profile Of Trace Elements In a Sediment Core Of a High-Altitude Lake Deposit At The Pyrenees, Spain

Depth concentration profiles of 26 elements, i.e. trace elements (As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Pb, Rb, Sr, V and Zn), lithophiles (Si, Al, Fe, Mn, Na, K, Mg, Ca and Ti) and nutrients (C, P, N, S) have been established in a sediment core collected at the Respomuso Lake (Pyrenees, Spain). This high altitude lake of glacier origin was transformed into reservoir in the fifties of last century. Correlations among the depth profiles of the above elements were established. HCl-extractable elements, which are better related to bioavailability, followed the profiles of total contents. Principal component analysis was applied to establish the binding behaviour of trace elements in the sediment matrix and, in turn, to search for their anthropogenic or natural sources. It was seen that Cu, Ni, Pb, Sr and Zn clustered together, and with exception of Sr, they were not clearly associated with any major component of the sediment. Their depth profiles correlate well with each other, hence indicating their presence as a result of atmospheric pollution. Redox-sensitive elements such as Fe and Mn follow a similar trend along the vertical profile. Depth profiles of As an Co correlate well with those of Fe and Mn. Principal component analysis showed that As, Co, Fe and Mn clustered together, which confirms the close association of As and Co with Fe-Mn oxyhydroxides. As concentrations in many strata exceed the ERM value, and therefore, significant biological effects are expected. Dissolution of minerals such as pyrite, chalcopyrite and galena taking part in the mineralogy of this area accounts for the As concentration found. Ba, Cr, Rb and V were associated with the sediment matrix (aluminosilicates), hence showing low mobility.     

Primary inoculum of Erwinia amylovora: alternative sources and viable but non-culturable state: A review

Journal of Plant Diseases and Protection - Fire blight is a complex and devastating plant disease caused by the necrotrophic bacterium Erwinia amylovora. One of the main factors that determine the...     

Effects of Drying Process on the Physicochemical Properties of Nopal Cladodes at Different Maturity Stages

Chemical proximate analysis was done in order to determine the changes of nutritional characteristics of nopal powders from three different maturity stages 50, 100, and 150 days and obtained by three different drying processes: freeze dried, forced air oven, and tunnel. Results indicate that nopal powder obtained by the process of freeze dried retains higher contents of protein, soluble fiber, and fat than the other two processes. Also, freeze dried process had less effect on color hue variable. No changes were observed in insoluble fiber content, chroma and lightness with the three different drying processes. Furthermore, the soluble fibers decreased with the age of nopal while insoluble fibers and ash content shows an opposite trend. In addition, the luminosity and hue values did not show differences among the maturity stages studied. The high content of dietary fibers of nopal pad powder could to be an interesting source of these important components for human diets and also could be used in food, cosmetics and pharmaceutical industry.     

Inhibitory Effect of Grapefruit Juice on the Genotoxic Damage Induced by Ifosfamide in Mouse

The consumption of grapefruit juice (GJ) has been associated with various activities potentially beneficial for human health, including protection against the DNA damage produced by various compounds. In the present report, we evaluated the capability of this juice to inhibit the rate of micronucleated polychromatic erythrocytes (MNPE) and sister chromatid exchanges (SCE) induced by the antineoplastic alkylating agent ifosfamide (IF). We tested the effect of administering 100, 500, and 1000 mg/kg of GJ in mouse and obtained the following results: a) with the high dose, a reduction of 72% in the rate of SCE induced by IF; b) a mean reduction of 65.3% in the rate of MNPE compared with the damage induced by IF at 48 h post-administration; c) no modification induced by GJ either on the cellular proliferation kinetics or in the mitotic index; and d) neither induction of bone marrow cytotoxicity by GJ nor a protective effect of the juice against the cytotoxicity induced by IF. These data showed a significant inhibitory effect of GJ against the chromosome damage induced by the tested agent; they also suggest the relevance of carrying out studies to clarify the involved mechanism of action as well as to determine the cancer chemopreventive capacity of the juice.     

Study of Structural and Thermal Changes in Endosperm of Quality Protein Maize During Traditional Nixtamalization Process

This work presents the study of the structural changes of the endosperm of Quality Protein Maize (QPM H-368C), modified by alkaline cooking at two different temperatures (72 and 92°C) and steeping time of 0–7 hr. Structural changes in the outermost 10% layers, the subsequent 10%, and the remaining 80% of the endosperm as a function of the steeping time were studied using scanning electron microscopy (SEM), X-ray diffraction, and differential scanning calorimetry (DSC) techniques. SEM images revealed that soft and hard endosperm have different shapes and packing factors. The X-ray diffraction patterns of the hard and soft endosperm from raw corn suggest that the hard endosperm consists mainly of amylopectin and has a bigger relative crystallinity quality than the soft endosperm. Samples cooked at 72 and 92°C with and without the (Ca(OH)₂ and steeped for 0, 3, and 7 hr, showed structural changes, X-ray diffraction patterns from the outermost 10% layers and subsequent 10% of the endosperm were completely amorphous. This fact is related to the total or partial gelatinization of the starch. The crystallinity in the internal layers of endosperm (remaining 80%) did not have significant changes after the treatments and exhibited the characteristic patterns of crystalline amylose and amylopectin. DSC measurements in the outermost layers of the endosperm did not exhibit the characteristic endothermic peak of starch (from 64 to 81°C) compared with the raw sample, while the endotherm peak for 80% of the endosperm internal layers appears in all cases (72 and 92°C). According to these results, a new definition of the nixtamalization process can be developed as follows. During the nixtamalization process there is a total gelatinization of the starch granules from the most external layers, and a partial gelatinization of the innermost internal layers of the endosperm.     

Detailed monitoring of white spot syndrome virus (WSSV) in shrimp commercial ponds in Sinaloa, Mexico by nested PCR

WSSV has caused great losses to the global shrimp industry in recent years. This virus can infect shrimps asymptomatically. However, once the clinical signs are developed, mortalities can reach 100% in 3-10 days. PCR has been extensively used to detect WSSV in a specific and sensitive manner. Nested PCR is even more sensitive than single-step PCR and had been used for the detection of WSSV in asymptomatic populations. In this work, a detailed monitoring of WSSV by nested PCR in shrimp commercial ponds in Guasave County, State of Sinaloa, Mexico, is presented. Five ponds from two different farms were monitored for growth and presence of WSSV. At the beginning of the culture, ponds from both farms showed no or very slight WSSV presence. A 3-day period of rain occurred at both farms 10 and 14 weeks of culture for farms 1 and 2, respectively. At this time, WSSV was widely distributed in the shrimp populations of farm 1 according to nested-PCR data, although no visual symptoms were observed. In ponds of farm 2, WSSV was present at low level. However, the number of PCR-positive groups was drastically increased in both farms by nested and single-step PCR. Abrupt fluctuations in temperature and salinity were documented in farm 2 after the rain, which may have contributed to the increasing of viral load in the pond's shrimp populations. Twelve days after the rain period, estimated mortalities of 80% occurred in farm 1. Nevertheless, the study ponds at farm 2 culture continued normally for three more weeks and were harvested successfully (52% and 67% of survival for ponds 1 and 2, respectively). The removal of 40% and 50% of shrimp population 2-4 days after the raining period may have contributed to the thriving of the cultures. Analyses of the presence of WSSV in individuals of both sexes indicated that there is no preference for this virus to infect male or female shrimp. Also, no differences in weight were found between WSSV infected and non-infected individual shrimps, as well as nested-PCR positive against single-step PCR positive organisms. Nested PCR is more useful to monitor shrimp cultures than single-step PCR since it allows knowing how widely distributed the virus is in asymptomatically populations.     

Iodine deficiency and its association with intelligence quotient in schoolchildren from Colima, Mexico

OBJECTIVE: To determine the prevalence of iodine deficiency, its causes and its association with intelligence quotient (IQ) in Mexican schoolchildren. DESIGN: Cross-sectional analytical study, in which determinations of thyroid gland size, urinary iodine excretion, IQ, iron nutritional status, physical anthropometry, family consumption of goitrogenic foods, type/origin and iodine saturation of salt consumed at home and coliform organisms in drinking water were performed, and the association of each variable with IQ scores was evaluated by multiple regression analyses. SETTING: Municipality of Cuauhtémoc, in Colima, Mexico (altitude: 600-2700 m above sea level). Sea salt is extracted manually nearby and often used for human consumption. Goitre remains present in the region despite over half a century of mandatory salt iodination in the country. SUBJECTS: Three hundred and three children, similar proportions of boys and girls, mean age 9.3 years, randomly selected from 19 public elementary schools. RESULTS: Overall goitre rate was 21.4%; low urinary iodine excretion was found in 19.5% of the children, high urinary iodine excretion in 32.0%. IQ scores were transformed into percentile values, with the following categorisation: < or = P5 (low IQ), 48.5%; > P5 to < or = P25 (below average), 24.2%; > P25 to < P75 (average), 18.8%; > or = P75 to < P95 (above average), 3.6%; > or = P95 (high IQ), 4.9%. Ninety-two per cent of the population used iodinated salt, but deficient iodine saturation (<50 ppm) was found in 86.8% of salt samples. The main goitrogenic foods consumed were peanuts (by 31.5% of the sample), cabbage (30.1%), broccoli (27.7%) and cauliflower (25.7%). Median counts of coliform organisms (colony-forming units/100 ml of drinking water) were: 207.5 (well water), 151 (cisterns), 52 (private homes), 25 (elementary schools) and 12 (kindergartens). Moderate iodine deficiency was associated (P < 0.05) with a 4.26 times higher risk of low IQ. CONCLUSIONS: There is a perturbing negative impact of these findings on human capital acquisition for the region and the country. More attention is needed to ensure effective salt iodination processes, particularly in regions where goitrogens may contribute to the negative effects of iodine deficiency on the intellectual development of children.     

Relationships between volatile production, fruit quality, and sensory evaluation in Granny Smith apples stored in different controlled-atmosphere treatments by means of multivariate analysis.

Aroma compounds, quality parameters, and sensory evaluation of Granny Smith apples were analyzed after 3, 5, and 7 months of cold storage in three controlled-atmosphere (CA) treatments, in which oxygen and carbon dioxide were held at 1, 2, and 3%. During poststorage ripening, the apples were kept at 20 degrees C for 1, 5, and 10 days before analytical measurements were made. The highest volatile emission was obtained after 5 months of storage in all CA treatments, reaching its highest value when a low-oxygen CA (LO) was used. Ultralow-oxygen CA (ULO) showed the highest ability to maintain apple firmness. The correlation among analytical and sensory parameters suggests that ethyl 2-methylbutyrate, 1-butanol, pentyl acetate, and tert-butyl propionate are the aroma compounds with the highest influence in the sensorial score. Concerning CA treatments, LO and ULO appear to be very valuable technologies for maintaining the sensorial quality even after 7 months of storage.