The development and release of maize fortified with provitamin A carotenoids in developing countries

Micronutrient deficiencies have been identified as major public health problems affecting a large part of the world's population. Biofortification of staple crops like maize has been proposed as one of the most cost effective and feasible approaches to combat micronutrient deficiencies. Studies have shown that provitamin A from biofortified crops is highly bioavailable and has the capacity to improve vitamin A status of vulnerable groups. Most people in sub-Saharan Africa subsist on maize and many people may benefit from consumption of provitamin A carotenoid biofortified maize, especially women and children. With the exception of transgenic golden rice, biofortified crops have received considerable acceptance by most communities. Negative perceptions associated with yellow maize do not affect orange maize, which is, for example, well-liked in rural Zambia. With proper policy frameworks and full commercialization, provitamin A maize can address the problem of vitamin A deficiencies among poor nations with maize-based diets.     

木薯叶粉中赭曲霉毒素A快速检测方法的建立

目的 开发快速检测方法检测木薯叶粉中的赭曲霉毒素A(Ochratoxins A, OTA)。方法 利用单克隆抗体和酶标抗原, 建立了竞争酶联免疫吸附测定法(enzyme-linked immunosorbent assay, ELISA)快速检测方法。用不同浓度的氯化钠甲醇水溶液、乙腈和磷酸盐缓冲液等作为样本提取液提取木薯叶粉中OTA, 用活性炭和稀释法减少样本基质干扰。结果 ELISA灵敏度为0.2 ng/mL, IC50为0.878 ng/mL。木薯叶粉用含氯化钠的70%甲醇水溶液提取, 离心后取上清5倍稀释, 样本回收率80%~121%, 检测限为5 μg/kg, 满足国标规定食品中OTA不超过5 μg/kg的要求, 检测时间为30 min, 一次可批量检测90个样本。结论 用本研究建立的ELISA方法检测木薯叶粉及其食品中的OTA含量结果准确、操作简单、成本低、时间短、重复性好, 适合基层批量筛查。     

Extraction and quantification of major carotenoids in processed foods and supplements by liquid chromatography

A simple, fast and robust method with minimum steps, small sample size and amounts of solvents was developed to determine major carotenoids contents in processed foods, tablets and gel capsules. The method involves dispersion of the sample in hot water (60 °C) with added butylated hydroxytoluene (BHT) in ethanol to minimize oxidation, followed by extraction with chloroform and analysis by liquid chromatography. Chromatographic parameters were: a C30 column protected with a C18 guard cartridge; gradient elution at the rate of 1.0 mL/min starting with 100% methanol (A) and ending with 40:60 (v/v) methanol/isopropanol (B); detection set at 450 nm for carotenoids, and 325 nm for retinol, retinyl acetate and retinol palmitate. The method exhibited: (i) high degree of repeatability (%rsd); (ii) linear calibration curves (r² ? 0.9998); (iii) low detection; and quantification limits. The method was validated with standard reference material 2383 for trans-β-carotene; and tested for α-, and β-carotenes, lutein, zeaxanthin, cryptoxanthin, trans-retinol in processed foods, tablets and gel supplements.     

Provitamin A carotenoids and ascorbic acid contents of the different types of orange juices marketed in Spain

The vitamin C and provitamin A carotenoids contents of 25 commercially available Spanish orange juices were studied. Large differences in the levels of these compounds were found. On average, ultrafrozen orange juices (UFOJ) and orange juices from the ecological agriculture (OJFEA) showed the highest ascorbic acid contents (518 and 412 mg/l respectively) among the different kinds of orange juices studied. Some disagreement between the declared and the actual amounts of vitamin C were found. Provitamin A carotenoids were determined by means of the corresponding standards. The monohydroxycarotenoid accompanying β-cyptoxanthin in orange juices was identified as the non-provitamin A carotenoid, zeinoxanthin, on the basis of the methylation test with acidified methanol. Unusually high contents of β-carotene (>0.5 mg/l) were found in two samples, which could indicate that substantial amounts of the pigment were added to those juices. The mandarin juice analyzed showed the highest provitamin A activity (359.3 retinol activity equivalents/l) Among the orange juices surveyed, UFO proved to be the best source of provitamin A (78.5 retinol activity equivalents/l, on average). The lowest contents were found in orange juices from concentrate (OJFC) (22.4 retinol activity equivalents/l, on average, without considering the orange juices with unusual β-carotene contents).     

Tannin levels in cassava,a comparison of methods of analysis

Low levels of tannins (proanthocyanidins) have been detected in dried cassava (Manihot esculenta Crantz) samples using standard methods of analysis based on extraction procedures. A direct vanillin assay method was compared with other direct methods of analysis based on acid hydrolysis and protein precipitation. The specificity of the methods is discussed in relation to the levels of tannins detected and their potential biological activity in freeze dried fresh and dried/processed cassava samples. The results are discussed with respect to the amount of indigestible material present in the samples. The results of these experiments indicate that tannins present in dried/processed cassava products may be a factor limiting their nutritional value.     

Identification and quantification of carotenoids by HPLC-DAD during the process of peach palm (Bactris gasipaes H.B.K.) flour

The identification and quantification of carotenoids has been carried out on tropical and non tropical fruits because of two important carotenoid's properties: as antioxidant compounds having a prevention role in some diseases, and as a source of provitamin A needed for a good human nutrition. This study aimed to identify carotenoids present during different steps for producing flour from Costa Rican peach-palm fruit (Bactris gasipaes H.B.K). Nine carotenoids were tentatively identified and quantified by HPLC-DAD in raw pulp, and 14 were detected in cooked pulp, the additional five being products of isomerization and hydroxylation of carotenoids in the raw pulp. The flour contained 13 carotenoids, one less (all-trans-??-criptoxanthin) than in cooked pulp, with the main one being all-trans ??-carotene. This carotenoid was also present in raw pulp at a concentration of 96.0 ± 1.7 ??g equiv. of ??-carotene g⁻¹ dw. The concentration decreased significantly (P < 0.05) during cooking and drying to reach a final concentration of 33.3 ± 1.0 ??g equiv. ??-carotene g⁻¹ dw in the flour. Flour production reduced (P < 0.05) the total carotenoid content from 373.4 to 237.7 ??g of ??-carotene g⁻¹ dw, with a final retention rate of 63.7% by the end of the process. Moreover, 9 of the 14 carotenoids account for high levels of provitamin A, which, even so, had decreased from 2723 retinol equivalents (RE) 100 g⁻¹ in raw pulp to 1614 RE 100 g⁻¹ in cooked pulp and 1289 RE 100 g⁻¹ in flour. Provitamin A level is still high when compared to other common provitamin A sources. Our study shows that while there is a change in the levels and profile of carotenoids during the peach-palm flour process, and a reduction of provitamin A value, peach-palm fruit is a great source of bioactive compounds.     

Vitamin C and carotenoids in organic and conventional fruits grown in Brazil

This study compared the concentration of vitamin C (ascorbic acid, AA, and dehydroascorbic acid, DHA) and carotenoids (lycopene and β-carotene) between three fruits produced by organic and conventional farming. Vitamin C and carotenoids were analysed by high-performance liquid chromatography. The Student t-test (α = 5%) was applied to determine differences between the organic and conventional production systems. AA content was significantly higher in organic acerola (4023.39 mg/100 g) compared to its conventional production (2294.53 mg/100 g). Conversely, AA content was significantly higher in conventional strawberries (42.45 mg/100 g) than the organic ones (30.74 mg/100 g). The conventional production also showed significantly higher contents of DHA (persimmon: 7.50 mg/100 g vs. 0.96 mg/100 g) and β-carotene (acerola: 6130.24 μg/100 g vs. 2486.38 μg/100 g) than the organic fruits. Lycopene was only detected in persimmons, but no significant difference was observed between farming systems. There was no evidence of the nutritional superiority of the organically grown fruits.     

Uncertainty estimation and in-house method validation of HPLC analysis of carotenoids for food composition data production

The method for separation and quantitative determination of the main carotenoids in food by high-performance liquid chromatography (HPLC) was in-house validated. Tomato (Lycopersicon esculentum M.) as food matrix was used to demonstrate its linearity, repeatability, intermediate precision, detection and quantification limits, sensitivity and bias. In addition, stability of carotenoids was studied in function of temperature and time. Method accuracy was quantified through measurement uncertainties estimate based on this validation study. Furthermore, a study was conducted to evaluate variability coming from location in an experimental field composed by 12 subfields. The use of two metal free reverse phase columns and an organic mobile phase based on acetonitrile, methanol and dichloromethane enabled the separation of the six target compounds (trans-α-carotene, trans-β-carotene, β-cryptoxanthin, all-lycopene, lutein, zeaxanthin) within a 30 min run; detection at 450 nm and external calibration allowed the quantification of the analytes. Carotenoids concentration and measurement uncertainty, in mg/100 g, in tomato varieties “lido” and “for salad” were, respectively, 1.0 ± 0.14 and 0.39 ± 0.056 for trans-β-carotene, 8 ± 2.0 and 2.3 ± 0.57 for all-lycopene and 0.10 ± 0.017 and 0.08 ± 0.015 for lutein; trans-α-carotene, β-cryptoxanthin and zeaxanthin were not detected in both varieties (detection limits, in μg/100 g, 0.81, 0.57 and 0.77, respectively). For β-carotene and lutein, uncertainty associated with the entire process including small-scale within-region variation was statistically different, at a significance level of 5%, from measurement uncertainty (which includes sampling in the laboratory).     

Resistance of maize to the maize weevil: III. Grain weight loss assessment and implications for breeding

The maize weevil (Sitophilus zeamais) is a significant pest of stored maize grain in tropical and subtropical regions worldwide. As a further step towards finding maize genotypes with acceptable levels of resistance to the maize weevil, 53 experimental maize hybrids that were generated in a North Carolina design II mating scheme, were evaluated for grain weight loss due to maize weevil damage under ambient temperature and humidity (ATH) conditions, in the on-station stock room at Harare, Zimbabwe. The study indicated that genotypic variation for grain weevil resistance was large (19%–57%) after five months of infestation by the maize weevils. A few F₂ populations with potential for use as sources of breeding new varieties for maize weevil resistance were identified. They displayed consistency of high performance (better than the standard control varieties) and showed a lower rate of grain weight loss due to the maize weevils over the five months in the stock room. The male and female GCA and SCA effects were highly significant (P ≤ 0.01) for maize weevil resistance, especially at two months after infestation, indicating that resistance was controlled by genes with both additive and non-additive effects, respectively. Further, the distribution of grain weight loss data for the hybrids was continuous and almost normal at the four intervals of data collection, clearly supporting that resistance was partial and possibly conditioned by minor genes with cumulative effects. Therefore, resistance could probably be improved by selection among the promising F₂ populations identified in this study. Although resistance was partial, a plot of grain weight loss of hybrids from the different categories demonstrated the advantage to farmers for growing a resistant variety (low percentage loss over time) compared to the susceptible ones that incurred significant grain weight losses. However, grain weight loss data were not significantly correlated with yield (r = 0.14; P > 0.05), suggesting that the traits are not mutually exclusive. Therefore, breeding for maize weevil resistance in these populations would not necessarily compromise grain yield. Our results demonstrate that there is potential in developing maize varieties with acceptable levels of maize weevil resistance through recurrent selection procedures which exploit both GCA and SCA effects with sustainable impact on food security and the environment.     

Carotenoids in cassava: Comparison of open-column and HPLC methods of analysis

Cassava leaves and tubers from six cultivars were analysed for carotenoids by both open-column chromatography and high-performance liquid chromatography (HPLC). The major carotenoids of leaves were the non-vitamin A carotenoid lutein (86-290 mg kg^?1 fresh weight (FW)) and the pro-vitamin A carotenoid β-carotene (13-78 mg kg^?1 FW). Immature leaves contained less than mature leaves. Tubers contained 0.1-3 mg kg^?1 FW of β-carotene and 0.05-0.6 mg kg^?1 FW of lutein. Carotenoids present in small amounts included α-, γ-, and §-carotenes and β-cryptoxanthin and others were separated and partially identified. Yellow tubers contain much more β-carotene than white tubers and cassava is a good source of pro-vitamin A carotenoids compared with other root crops. Both methods gave similar results for β-carotene and lutein, but the open-column method did not allow separation and quantitation of carotenoids present in small amounts. HPLC separated many carotenoids, but most peaks could not be identified for lack of reference compounds. A great advantage of open-column chromatography for developing countries is its use of simple equipment and readily available reagents and solvents compared with HPLC, which requires complex equipment needing careful maintenance and expensive solvents. The open-column method is more labour intensive but this is not a constraint in developing countries.     

Rheological and textural properties of lafun,a stiff dough,from improved cassava varieties

We studied the textural and rheological (viscoelastic) properties of fresh lafun dough, a fermented cassava product, and their changes during storage at 45 °C for 5 and 24 h, in order to determine after-cooking storability. Lafun flours were produced from three types of cassava varieties: seven improved white-fleshed varieties, seven improved provitamin A carotenoids (pVAC) varieties and two local white-fleshed varieties; and processed into lafun doughs. Pasting properties of the flours were assessed. Flours from local varieties had pasting profiles with highest viscosities, while pVAC flours had the lowest. The three types of cassava varieties varied significantly in most of their pasting properties. Four promising improved varieties were identified, based on high peak viscosity (55.8–61.5 P) and stiffer texture than local varieties during storage. Undesirable varieties were also found, which softened during storage instead of hardening. Optimum texture of lafun dough was obtained after 5 h of storage.     

Survey for aflatoxins, ochratoxin A, zearalenone and fumonisins in maize imported into the United Kingdom

This survey examined 140 samples of raw maize as received at ports or at major maize mills in the UK and 12 after initial cleaning. Samples were examined for aflatoxins B₁, B₂, G₁ and G₂, ochratoxin A, zearalenone and fumonisins B₁, B₂ and B₃ using fully validated analytical HPL C methods with detection limits of 0.1 mu g/kg for each aflatoxin and ochratoxin A, 4 mu g/ kg for zearalenone and 10 mu g/kg for each fumonisin. 95.0% and 92.1% of samples met the new EC statutory maximum permissible level for total aflatoxins and aflatoxin B₁ respectively. The maximum concentration of ochratoxin A found was 1.5 mu g/kg. Zearalenone and fumonisins were detected in almost every sample with 41.7% of maize containing more than 100 mu g/kg of zearalenone and 48% of samples containing more than 1000 mu g/kg total fumonisins. Initial cleaning of raw maize reduced aflatoxin concentrations by about 40% and total fumonisins by 32%.     

Effects of processing on anthocyanins,carotenoids and vitamin C in summer fruits and vegetables

The purpose of this study was to evaluate the effects of processing, i.e. heating (98 °C, 10 min), freezing (−20 °C) and freeze-drying on anthocyanins, carotenoids, and vitamin C in summer fruits and vegetables, i.e. cherries, nectarines, apricots, peaches, plums, carrots and red bell peppers. The commodities were collected from growers located in the Otago region (namely Cromwell, Roxburgh, Mosgiel and Clinton), New Zealand. The results revealed that each commodity contained different contents of phytochemicals. The content and the process stability of phytochemicals in each commodity were influenced by the geographical location of the growers. In general, a high content of phytochemicals was found in summer fruits and vegetables grown in Otago compared to those grown in the Northern Hemisphere, e.g. anthocyanins in cherries, nectarines, peaches and plums; total carotenoids in red bell peppers and nectarines and vitamin C in cherries, peaches, red bell peppers and carrots. Heating and freezing enhanced the release of membrane bound anthocyanins, resulting in higher content after processing compared to fresh commodities. In the commodities studied, with the exception of red bell peppers, the stability of ascorbic acid was increased if ascorbic acid oxidase was inactivated for example by heating.     

Provitamin A carotenoids in table olives according to processing styles, cultivars, and commercial presentations

The concentration of provitamin A carotenoids in table olives was determined. Only -carotene was found in all commercial presentations. -carotene was also present in final products containing carrots. Concentrations of -carotene, referring to 100 g edible portion, ranged from an average of 197 to 1,387 g in green olives, from 37 to 726 g in directly brined olives and from 39 to 333 in ripe (darkened by oxidation) olives. Thus, some commercial presentations of table olives can be considered reasonable sources of provitamin A. Several groups were formed within elaboration styles and cultivars, according to commercial presentations. Their averages and other statistical estimations are also given. These results may be used by the industry as a source of information for nutritional labelling or by nutritionists to estimate provitamin A intakes in diets that include table olives.     

Changes in carotenoids including geometrical isomers and ascorbic acid content in orange–carrot juice during frozen storage

Fruits and vegetables are highly perishable foods, which explains the need to apply preservation techniques, such as freezing. The aim is to combine shelf life extension with maintenance of sensory and nutrient characteristics. The stability of orange–carrot juice stored at –40 °C for 132 days was studied. The ascorbic acid and carotene contents and the influence of storage time were analysed. Carotenes were identified and quantified by liquid chromatography and ascorbic acid was determined by differential pulse polarography. The initial concentration of ascorbic acid was 27.09 mg/100 ml and decreased by 4.1% during the storage period. Vitamin A activity in the orange–carrot juice increased during the period studied, fitting a linear model (R²=0.87). Of the 14 carotenes identified, only antheraxanthin and the mixture of 9-cis-violaxanthin and neoxanthin decreased in concentration during the storage period.     

Mycobiota and mycotoxin contamination of maize flours and popcorn kernels for human consumption commercialized in Spain

Mycobiota and co-occurrence of aflatoxins, citrinin, ochratoxin A and zearalenone in 30 samples of maize flours and 30 of popcorn kernels purchased in Spain for human consumption were determined. The mycotoxin-producing ability of Aspergillus, Fusarium and Penicillium spp. was also studied.     

Integrated sustainable process design framework for cassava biobased packaging materials: Critical review of current challenges,emerging trends and prospects

BackgroundCassava represents a reasonable share in biobased material development globally. The production of its biopolymer derivatives using conventional techniques/methods is accompanied by significant wastes with potential negative environmental impact. Among the biopolymer derivatives, starch dominates as lone additive in cast matrices with packaging limitations, requiring other biopolymer derivatives, and/or external-source modifiers for matrix improvement. Exploiting integrated sustainable engineering process design of all biopolymer derivatives, is a novel approach in designing efficient system of cassava biobased materials for food and non-food applications.Scope and approachA critical review on the current and emerging techniques and methodologies to address cassava wastes and challenges of cassava research for application on biobased packaging are provided. The potential of integrated sustainable engineering process design framework for packaging system is discussed, and prospects for improvement suggested.Key findings and conclusionsChallenges of significant waste generated during conventional processing and on the application process aiming at tailoring materials to industrial needs are reported. These materials should be improved using a holistic approach reflecting the target products, variable environment, minimising production costs and energy. Use of novel material resources, eliminating waste, and employing a standardised methodology via desirability optimisation, present a promising process integration tool for development of sustainable cassava biobased systems.     

Development of a food product profile for boiled and steamed sweetpotato in Uganda for effective breeding

This study sought to understand user preferences of raw, boiled and steamed sweetpotato, a staple food in Uganda. A sequential methodology involving state of knowledge review, gendered food mapping, processing diagnosis and consumer testing was used in Lira and Kamwenge districts. Preferred raw sweetpotato characteristics were large roots (≥ 3 cm diameter) with a sweet taste, smooth skin and hard texture, while mealiness, sweet taste and good sweetpotato smell were important attributes for boiled sweetpotato. Processors, mostly women, highlighted ease of peeling and sappiness of raw roots. There were gender differences in quality characteristic preferences and perceived importance. The released variety, NASPOT 8, had the highest overall liking in Kamwenge and was well liked in Lira. Penalty analysis of consumer data showed that sweetness and firmness were key drivers of overall liking. The results will support breeding programmes in meeting specific end-user product profiles, selection criteria and uptake of new varieties.