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The U.S. Food and Drug Administration requires food processors to implement and validate processes that will result in significantly minimizing or preventing the occurrence of hazards that are reasonably foreseeable in food production. During production of fresh-cut leafy vegetables, microbial contamination that may be present on the product can spread throughout the production batch when the product is washed, thus increasing the risk of illnesses. The use of antimicrobials in the wash water is a critical step in preventing such water-mediated cross-contamination; however, many factors can affect antimicrobial efficacy in the production of fresh-cut leafy vegetables, and the procedures for validating this key preventive control have not been articulated. Producers may consider three options for validating antimicrobial washing as a preventive control for cross-contamination. Option 1 involves the use of a surrogate for the microbial hazard and the demonstration that cross-contamination is prevented by the antimicrobial wash. Option 2 involves the use of antimicrobial sensors and the demonstration that a critical antimicrobial level is maintained during worst-case operating conditions. Option 3 validates the placement of the sensors in the processing equipment with the demonstration that a critical antimicrobial level is maintained at all locations, regardless of operating conditions. These validation options developed for fresh-cut leafy vegetables may serve as examples for validating processes that prevent cross-contamination during washing of other fresh produce commodities.

The underutilized Amaranthus leafy vegetables are a unique basis of pigments such as β-cyanins, β-xanthins, and betalains with radical scavenging capacity (RSC). They have abundant phytonutrients and antioxidant components, such as pigments, vitamins, phenolics, and flavonoids. Eight selected genotypes (four genotypes from each species) of underutilized Amaranthus leafy vegetables were evaluated for phytonutrients, pigments, vitamins, phenolics, flavonoids, and antioxidants in a randomized complete block design under ambient field conditions with three replicates. The studied traits showed a wide range of variations across eight genotypes of two species of Amaranthus leafy vegetables. The highest fat, β-xanthins, K, dietary fiber, Mg, β-cyanins, Mn, chlorophyll ab, Zn, TP, TF, betalains, chlorophyll a content, and (RSC) (DPPH) and RSC (ABTS+) were obtained from A. tricolor accessions. Conversely, the highest protein, Cu, carbohydrates, Ca, and chlorophyll b content were obtained from A. lividus accessions. The highest dry matter, carotenoids, Fe, energy, and ash were obtained from A. tricolor and A. lividus. The accession AT2 confirmed the highest vit. C and RSC (DPPH) and RSC (ABTS+); AT5 had the highest TP content; and AT12 had the highest TF content. A. tricolor accessions had high phytochemicals across the two species, such as phytopigments, vitamins, phenolics, antioxidants, and flavonoids, with considerable nutrients and protein. Hence, A. tricolor accessions can be used as high-yielding cultivars comprising ample antioxidants. The correlation study revealed that vitamin C, pigments, flavonoids, β-carotene, and phenolics demonstrated a strong RSC, and showed a substantial contribution to the antioxidant potential (AP) of A. tricolor. The investigation exposed that the accessions displayed a plentiful origin of nutritional values, phytochemicals, and AP with good quenching ability of reactive oxygen species (ROS) that provide enormous prospects for nourishing the mineral-, antioxidant-, and vitamin-threatened community.

The current trend for substituting synthetic compounds with natural ones in the design and production of functional and healthy foods has increased the research interest about natural colorants. Although coloring agents from plant origin are already used in the food and beverage industry, the market and consumer demands for novel and diverse food products are increasing and new plant sources are explored. Fresh vegetables are considered a good source of such compounds, especially when considering the great color diversity that exists among the various species or even the cultivars within the same species. In the present review we aim to present the most common species of colored vegetables, focusing on leafy and fruit vegetables, as well as on vegetables where other plant parts are commercially used, with special attention to blue color. The compounds that are responsible for the uncommon colors will be also presented and their beneficial health effects and antioxidant properties will be unraveled.

In the past 20 years, very little progress has been achieved in reducing food insecurity, child malnutrition and hunger in Africa. Under-nutrition and micronutrients deficiencies are widespread and affect mainly women and children. To address these problems, increased consumption of African leafy vegetables is promoted as sources of both micronutrients and bio-active compounds. Widely promoted African leafy vegetables include Amaranthus spp., a taxonomic group cultivated worldwide. Species of this genus are used as pseudo-cereals in Europe and America, and are mostly planted as vegetables in Africa. Amaranthus has been rediscovered as a promising food crop mainly due to its resistance to heat, drought, diseases and pests, and the high nutritional value of both seeds and leaves. Leaves are rich in proteins and micronutrients such as iron, calcium, zinc, vitamin C and vitamin A. All parts of the plant are used as medicine to heal many diseases in African communities. This paper focuses on leafy amaranths traditionally utilized on the continent. It briefly reviews the current knowledge on taxonomy, ecology, nutritional and nutraceutical value, production and cultivation systems, reproductive biology, genetic resources and breeding of amaranths. Species of interest include: A. blitum, A. caudatus, A. cruentus, A. dubius, A. hypochondriacus, A. spinosus, A. thunbergii, A. tricolor, and A. viridis. Research and development opportunities on nutritive and nutraceutical properties, production and commercialization, taxonomic evaluation and breeding perspectives were explored.

Inadequate consumption of micronutrient-dense foods such as vegetables and meat are an important contributing cause for anemia and deficiencies of iron and vitamin A in rural communities of Tanzania. A cross-sectional study was conducted in 2016 to examine nutritional and micronutrient status and their associations to the diet of female small-scale farmers in the sub-humid Kilosa (n = 333) and the semi-arid Chamwino (n = 333) districts, in the Morogoro and Dodoma region. An overall higher prevalence of overweight (19.7%) and obesity (7.1%) than of underweight (5.9%) was detected. Significantly more women in the two villages of Kilosa (27–40%) than in the two villages of Chamwino district (19–21%) were overweight/obese, but also more frequently had anemia (34–41% vs. 11–17%), iron deficiency (24–32% vs. 15–17%), and low serum retinol (21–24% vs. 8–9%). Overall, only a small proportion of women reached recommended daily micronutrient intakes: 27% for vitamin A, 17% for iron, 7% for zinc, and 12–38% for B-vitamins. The amount of dark green leafy vegetables (DGLV) consumed was the main determinant of vitamin A and iron intake by women in Chamwino and corresponded to higher hemoglobin, serum retinol and iron status than in the villages of the Kilosa district; in agreement, DGLV consumption also predicted iron and vitamin A intake in Kilosa district. DGLV consumed with wholemeal millet was advantageous in terms of women’s vitamin A and iron intake and status over the predominantly maize-rice-based diet lacking vegetables.

Sweet basil (Ocimum basilicum L.) is an aromatic, tender leafy green cultivated for the fresh market and industrial processing. Like many other leafy vegetables, this species can be harvested more than once to increase productivity. Although the cut-and-come-again (CC) harvest strategy is widespread in basil, not much is known about the effect of the cut. In this work, we examined differences in biomass, physiology, nutrient use efficiency and antioxidant capacity of basil leaves from two successive harvests. Moreover, we also performed an untargeted metabolomics analysis to reveal variations in the leaf metabolite profile. The data indicated that the cut affected many of the parameters under investigation, including a modest reduction of yield (−20%), of nitrogen use efficiency (−21%) and of some quality attributes such as the antioxidant capacity (−16%) and the nitrate content in leaves (+48%). Moreover, leaves of successive cuts displayed a significant variation of the profile of bioactive compounds, characterized by an overall decrease of phenylpropanoids and an increase in terpenoids. Our data revealed the impact of CC harvesting strategy in basil, and that this strategy offers the possibility to yield leaves with different metabolomics profiles and quality attributes.

Due to the advantages of improving vegetable quality and reducing labor, technology for the orderly harvesting of green leafy vegetables has always been the focus of research. The core of the technology is the clamping and conveying device. At present, technology for the orderly harvesting of green leafy vegetables has several difficult problems, such as the plugging of the clamping and conveying device, great damage caused by mechanical clamping and high transportation loss. A green leafy vegetable is essentially a viscoelastic body and plastic deformation is an important index to measure its mechanical damage. Therefore, based on vegetable linear viscoelastic characteristics, we determined the deformation and plastic damage mechanism caused by orderly clamping and conveying. A rheological constitutive model and mathematical equations of the damage deformation value were constructed for the green leafy vegetable mechanical clamping process. Viscoelastic parameters of green leafy vegetable samples were obtained by creep experiments. The elastic clamping force and clamping spacing were analyzed systematically when the flexible clamping and conveying device was clamping, conveying and collecting. Under different spring stiffness and clamping time combinations, green leafy vegetable plastic damage deformation values were calculated and the vegetable damage regularity analyzed. After comprehensive consideration, we concluded that, when the harvester forward speed was 0.6 km/h, the optimal parameter combination of the flexible clamping and conveying device was a conveying roller rotation speed of 80 r/min, and a spring stiffness combination of 2.0 N/mm and 0.6 N/mm. Finally, a bench test verified that the mechanized harvest effect was best under a combination of parameters. Thus, we proved that the method is appropriate for studying the effects of clamping and conveying devices on green leafy vegetable damage based on viscoelastic rheological characteristics.

Over the last 10 years, some high-profile foodborne illness outbreaks have been linked to the consumption of leafy greens. Growers are required to complete microbiological risk assessments (RAs) for the production of leafy crops supplied either to retail or for further processing. These RAs are based primarily on qualitative judgements of hazard and risks at various stages in the production process but lack many of the steps defined for quantitative microbiological RAs by the Codex Alimentarius Commission. This article is based on the discussions of an industry expert group and proposes a grower RA approach based on a structured qualitative assessment, which requires all decisions to be based on evidence and a framework for describing the decision process that can be challenged and defended within the supply chain. In addition, this article highlights the need for evidence to be more easily available and accessible to primary producers and identifies the need to develop hygiene criteria to aid validation of proposed interventions.

The aim of this study was to determine the mineral nutritive value of different traditional African green leafy vegetable (GLV) dishes and their composite meals with fortified and unfortified maize porridge. The mineral (iron, zinc, and calcium) and antinutrient (phytate, total phenolics, and tannins) contents and in vitro bioaccessibility of iron and zinc were analyzed. The iron and zinc contents and bioaccessibilities were used to calculate contribution these dishes and meals could make toward the recommended daily requirements and absolute requirements of vulnerable populations. It was found that the GLV dishes contained average amounts of zinc (2.8–3.2 mg/100 g, dry base [db]), but were high in both iron (12.5–23.4 mg/100 g, db) and antinutrients (phytate 1420–2089 mg/100 g, db; condensed tannins 105–203 mg/100 g, db). The iron bioaccessibility and amount of bioaccessible iron ranged between 6.7% and 45.2% and 0.9 and 5.11 mg/100 g, db, respectively. The zinc bioaccessibility and amount of bioaccessible zinc ranged between 6.4% and 12.7% and 0.63 and 1.63 mg/100 g, db, respectively. Importantly, although compositing the GLV dishes with fortified maize porridges decreases the iron and zinc contents, because of the low antinutrient content of the maize meal, the amount of bioaccessible iron and zinc in the meal increases. •This study investigated the mineral nutritional value of green leafy vegetable (GLV) dishes and composite and maize porridge meals.•GLV dishes contained average amounts of zinc, but were high in both iron and antinutrients.•Compositing the GLV dishes with fortified maize porridge decreased the iron and zinc contents.•The low antinutrient content of the maize porridge, led to increased amounts of bioaccessible iron and zinc in the meals.

Loss of seed viability, poor and delayed germination, and inaccessibility to high-quality seeds are key bottlenecks limiting all-year-round production of African traditional leafy vegetables (TLVs). Poor quality seeds are the result of several factors including harvest time, storage, and conservation conditions, and seed dormancy. While other factors can be easily controlled, breaking seed dormancy requires thorough knowledge of the seed intrinsic nature and physiology. Here, we synthesized the scattered knowledge on seed dormancy constraints in TLVs, highlighted seed dormancy regulation factors, and developed a conceptual approach for molecular genetic analysis of seed dormancy in TLVs. Several hormones, proteins, changes in chromatin structures, ribosomes, and quantitative trait loci (QTL) are involved in seed dormancy regulation. However, the bulk of knowledge was based on cereals and Arabidopsis and there is little awareness about seed dormancy facts and mechanisms in TLVs. To successfully decipher seed dormancy in TLVs, we used Gynandropsis gynandra to illustrate possible research avenues and highlighted the potential of this species as a model plant for seed dormancy analysis. This will serve as a guideline to provide prospective producers with high-quality seeds.