Remodeling the Isoprenoid Pathway in Tobacco by Expressing the Cytoplasmic Mevalonate Pathway in Chloroplasts

Metabolic engineering to enhance production of isoprenoid metabolites for industrial and medical purposes is an important goal. The substrate for isoprenoid synthesis in plants is produced by the mevalonate pathway (MEV) in the cytosol and by the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway in plastids. A multi-gene approach was employed to insert the entire cytosolic MEV pathway into the tobacco chloroplast genome. Molecular analysis confirmed the site-specific insertion of seven transgenes and homoplasmy. Functionality was demonstrated by unimpeded growth on fosmidomycin, which specifically inhibits the MEP pathway. Transplastomic plants containing the MEV pathway genes accumulated higher levels of mevalonate, carotenoids, squalene, sterols, and triacyglycerols than control plants. This is the first time an entire eukaryotic pathway with six enzymes has been transplastomically expressed in plants. Thus, we have developed an important tool to redirect metabolic fluxes in the isoprenoid biosynthesis pathway and a viable multigene strategy for engineering metabolism in plants

Olives! Scientists Take a New Look at an Ancient Crop

Though the price makes you wince, you might just buy that bottle of your favorite olive oil anyway. Perhaps it’s exactly what you want for the salad dressing you’re making tonight and for your special stir-fry on the weekend. But are you really getting what you paid for? A bottle proclaiming that it is olive oil might actually include another, lessexpensive vegetable oil derived from, for example, safflower or canola. Mislabeling is of concern not just to shoppers, retailers, and chefs, but also to America’s olive growers, olive oil processors, and more—especially those newly entering the U.S. olive oil market. California, which already produces the bulk of the nation’s olives, is experiencing a resurgence of interest in producing more of this popular vegetable oil, even in the face of significant international competition: Today, about 98 percent of all olive oil consumed in the United States is imported. Scientists at the Agricultural Research Service’s Western Regional Research Center in Albany, California, are contributing research findings that may strengthen the domestic olive oil industry. Talwinder Kahlon and Ken (Jiann-Tsyh) Lin, for instance, have developed analytical methods that can be used to assure the authenticity of olive oil. Rebecca Milczarek is investigating opportunities for making better use of the olive-milling byproducts that are left once the plump fruit, or “drupe,” has been processed to extract its oil. Mendel Friedman and colleagues have shown the effectiveness of olive powder for a perhaps surprising task: keeping hamburger patties safe to eat

High-Protein Nutritious Flatbreads and an Option for Gluten-Sensitive Individuals

Whole grain quinoa and wheat, high-protein vegetable flatbreads were evaluated by tasters and a physical analysis was conducted. The objective was to produce nutritious, tasty gluten-free (quinoa) as well as gluten-containing (wheat) flatbreads. Flatbreads were Quinoa Peanut Oilcake Broccoli (QPCBROC), Wheat Peanut Oilcake Broccoli (WPCBROC), Quinoa Peanut Oilcake Beets (QPCBEET) and Wheat Peanut Oilcake Beets (WPCBEET). Peanut Oilcake would increase protein and add value to this farm byproduct. Bile acid binding broccoli and beets with cholesterol-lowering potential were used. Tasters preferred QPCBROC flatbreads for all sensory parameters. Acceptance of flatbreads was QPCBROC (83%), WPCBROC (70%), QPCBEET (78%) and WPCBEET (69%); these values were statistically similar. The objective of ≥25% protein content was exceeded by 5–8% and that of ≥70% acceptance was adequately achieved. These flatbreads were low in fat (5–6%) and contained essential minerals (4%) with only ≤1% added salt. Porosity and expansion data suggest that these flatbreads would take up relatively little shelf space. These flatbreads require only three ingredients and can be made in a household kitchen or by commercial production. These flatbreads offer a nutritious, tasty choice for all, and quinoa flatbreads offer an option for gluten-sensitive individuals

Acrylamide Content of Experimental Flatbreads Prepared from Potato, Quinoa, and Wheat Flours with Added Fruit and Vegetable Peels and Mushroom Powders

Flatbreads are a major food consumed worldwide. To mitigate an undesirable safety aspect of flatbreads that might be associated with the potentially-toxic compound acrylamide, we recently developed recipes using a variety of grains that resulted in the production of low-acrylamide flatbreads. To further enhance the functionality of flatbreads, we have developed, in this work, new experimental flatbreads using potato, quinoa, and wheat flours supplemented with peel powders prepared from commercial nonorganic and organic fruits and vegetables (apples, cherry tomatoes, melons, oranges, pepino melons, sweet potato yams), potato peels, and mushroom powders (Lion’s Mane, Hericium erinaceus; Reishi, Ganoderma lucidum; and Turkey Tail, Trametes versicolor). These additives have all been reported to contain beneficial compositional and health properties. The results of fortification of the baked flatbreads showed either no effect or increases in acrylamide content by unknown mechanisms. Since the additives did not increase the acrylamide content of the quinoa flour flatbreads for the most part, such supplemented quinoa flatbreads have the potential to serve as a nutritional, gluten-free, low-acrylamide, health-promoting functional food. Mushroom powder-fortified wheat flatbreads with relatively low acrylamide content may also have health benefits

Sensory evaluation of gluten-free quinoa whole grain snacks

Sensory evaluation of quinoa gluten-free whole grain low fat and salt snacks was conducted. The snacks were Quinoa, Quinoa-Cayenne Pepper, Quinoa-Ginger and Quinoa-Turmeric. Cayenne pepper, ginger and turmeric are common spices that contain health promoting nutrients. Cayenne pepper has been associated with enhancing heat production. Ginger has been reported to improve blood flow and prevent joint pains. Turmeric has been observed to have wound healing potential. All the snacks contained 6% corn oil and 2% salt. Snack dough was prepared using 120 mL water for 100 g dry ingredients. About 20 g of snack dough was placed on center of preheated KrumKake Express Baker and cooked for 2 min. Seventy in-house volunteers judged Color/Appearance of Quinoa, Quinoa-Cayenne Pepper and Quinoa-Ginger snacks significantly (p ≤ 0.05) higher than Quinoa-Turmeric snacks. Odor/Aroma of Quinoa-Ginger snacks was significantly higher than other snacks tested. Texture/Mouth-feel of Quinoa-Cayenne Pepper, Quinoa-Ginger and Quinoa-Turmeric snacks was similar and significantly higher than Quinoa snacks. Taste/Flavor and Acceptance was similar in four kinds of snacks tested. Water activity of all the snacks tested ranged from 0.41–0.55 suggesting that these snacks were crispy with good antimicrobial stability. These snacks would be quite filling due to their expansion of 2.6–3.1 times due to high porosity. Acceptance of snacks tested was Quinoa 79%, Quinoa-Cayenne Pepper 77%, Quinoa-Ginger 73% and Quinoa-Turmeric 70%. These snacks contained only 3–4 ingredients and could be made in any house kitchen or commercial production. Acceptance of 70–79% is very desirable. These healthy nutritious gluten-free quinoa snacks offer choice for all including vegetarians and individuals hypersensitive to gluten

Acrylamide Content of Experimental Flatbreads Prepared from Potato, Quinoa, and Wheat Flours with Added Fruit and Vegetable Peels and Mushroom Powders

Flatbreads are a major food consumed worldwide. To mitigate an undesirable safety aspect of flatbreads that might be associated with the potentially-toxic compound acrylamide, we recently developed recipes using a variety of grains that resulted in the production of low-acrylamide flatbreads. To further enhance the functionality of flatbreads, we have developed, in this work, new experimental flatbreads using potato, quinoa, and wheat flours supplemented with peel powders prepared from commercial nonorganic and organic fruits and vegetables (apples, cherry tomatoes, melons, oranges, pepino melons, sweet potato yams), potato peels, and mushroom powders (Lion's Mane, Hericium erinaceus; Reishi, Ganoderma lucidum; and Turkey Tail, Trametes versicolor). These additives have all been reported to contain beneficial compositional and health properties. The results of fortification of the baked flatbreads showed either no effect or increases in acrylamide content by unknown mechanisms. Since the additives did not increase the acrylamide content of the quinoa flour flatbreads for the most part, such supplemented quinoa flatbreads have the potential to serve as a nutritional, gluten-free, low-acrylamide, and health-promoting functional food. Mushroom powder-fortified wheat flatbreads with relatively low acrylamide content may also have health benefits

Remodeling The Isoprenoid Pathway In Tobacco By Expressing The Cytoplasmic Mevalonate Pathway In Chloroplasts

Metabolic engineering to enhance production of isoprenoid metabolites for industrial and medical purposes is an important goal. The substrate for isoprenoid synthesis in plants is produced by the mevalonate pathway (MEV) in the cytosol and by the 2-C-methyl-. d-erythritol 4-phosphate (MEP) pathway in plastids. A multi-gene approach was employed to insert the entire cytosolic MEV pathway into the tobacco chloroplast genome. Molecular analysis confirmed the site-specific insertion of seven transgenes and homoplasmy. Functionality was demonstrated by unimpeded growth on fosmidomycin, which specifically inhibits the MEP pathway. Transplastomic plants containing the MEV pathway genes accumulated higher levels of mevalonate, carotenoids, squalene, sterols, and triacyglycerols than control plants. This is the first time an entire eukaryotic pathway with six enzymes has been transplastomically expressed in plants. Thus, we have developed an important tool to redirect metabolic fluxes in the isoprenoid biosynthesis pathway and a viable multigene strategy for engineering metabolism in plants. © 2011