Laban K. Rutto

Mineral Properties and Dietary Value of Raw and Processed Stinging Nettle (Urtica dioica L.)

Stinging nettle (Urtica dioica L.) has a long history of usage and is currently receiving attention as a source of fiber and alternative medicine. In many cultures, nettle is also eaten as a leafy vegetable. In this study, we focused on nettle yield (edible portion) and processing effects on nutritive and dietary properties. Actively growing shoots were harvested from field plots and leaves separated from stems. Leaf portions (200 g) were washed and processed by blanching (1 min at 96–98°C) or cooking (7 min at 98-99°C) with or without salt (5 g·L−1). Samples were cooled immediately after cooking and kept in frozen storage before analysis. Proximate composition, mineral, amino acid, and vitamin contents were determined, and nutritive value was estimated based on 100 g serving portions in a 2000 calorie diet. Results show that processed nettle can supply 90%–100% of vitamin A (including vitamin A as β-carotene) and is a good source of dietary calcium, iron, and protein. We recommend fresh or processed nettle as a high-protein, low-calorie source of essential nutrients, minerals, and vitamins particularly in vegetarian, diabetic, or other specialized diets.

Textural and Microbiological Qualities of Vegetable Soybean (Edamame)Affected by Blanching and Storage Conditions

Vegetable soybean (edamame) is a highly perishable product. Blanching combined with cold storage is an excellent preservation method to extend edamame shelf-life. The effects of different blanching and storage conditions on textural and microbiological qualities of in-pod edamame were investigated. Blanching for 2.5 min or longer at 100°C water reduced peroxidase activity by over 98%. The thermal denaturation temperature of edamame beans increased 30oC by blanching. The durations of blanching and refrigerated storage significantly influenced green color intensity and hardness of edamame beans. Green color intensity peaked as blanching time increased to 5 min, while the hardness of the beans decreased during blanching and cold storage. Yeast, mold, and total coliform bacteria were significantly reduced by blanching, and there was no significant increase in yeast and mold counts during refrigeration for ≤12 days. Addition of calcium chloride did not significantly enhance bean quality.

Genetic analysis of edamame seed composition and trait relationships in soybean lines

Edamame, a vegetable or specialty soybean (Glycine max) with high nutritional and market value, is relatively new to North America. Because of its health and nutritional benefits and globalized trade, the edamame market and acreage in the United States are steadily increasing. To facilitate edamame breeding and commercial production, we genetically analyzed edamame seed composition using 86 breeding lines and cultivars developed in the U.S. Significant genotypic differences based on a single year or 2-year joint analysis were observed for most traits investigated, including protein, oil, dietary fiber, starch, sucrose, stachyose and total sugar content. No significant genotypic difference was observed for ash content in both years and for raffinose content in year 2016. Yearly differences were also significant except for sucrose, stachyose and total sugar. Genotype-by-year interaction was significant for protein, sucrose, raffinose and total sugar, but insignificant for other traits. The heritability was high and relatively stable for protein and oil content, followed by stachyose content, but was low for ash and starch content. The heritability for sucrose, total sugar and dietary fiber content varied from 38 to 75%. Genotypic correlations were insignificant among most traits. However, protein content was negatively correlated with oil content and dietary fiber, but positively associated with stachyose. Oil content was negatively correlated with starch and individual sugars. Although positive phenotypic or Pearson’s correlation existed between total sugar content and individual sugars, and between sucrose and starch content, their genotypic correlations were insignificant.

Genetic Vulnerability and Crop Loss: The Case for Research on Underutilized and Alternative Crops

The confluence of global climate change and population growth has brought to greater focus the question of how to satisfy future demand for food and fiber necessary to sustain current standards of living. Inevitably, agriculture will be called upon to do more at a time when established crops and cropping systems must confront new environmental and socio-economic challenges. Current efforts to preserve and characterize crop wild relatives and other genetic resources that could help crops meet future biotic and abiotic challenges are a direct response to the question. This chapter not only reiterates the importance of in situ and ex situ genetic conservation, it draws attention to the urgent need for investment in research on underutilized and alternative crops. The urgency relates directly to the fact that most of these crops are found in global biodiversity hotspots that are currently undergoing rapid environmental and socio-economic change.