Nutritional, physicochemical, and functional properties of Hawaiian taro (Colocasia esculenta) flours: A comparative study.

Taro (Colocasia esculenta) flour is a viable carbohydrate alternative and a functional additive for food formulation; however, different taro varieties may possess distinct characteristics that may influence their suitability for food production. This study evaluated the nutritional, physicochemical, and functional properties of flours from five Hawaiian taro varieties: Bun-Long, Mana Ulu, Moi, Kaua'i Lehua, and Tahitian. Tahitian, Bun-long, and Moi had high total starch contents of 40.8, 38.9, and 34.1 g/100 g, respectively. Additionally, Moi had the highest neutral detergent fiber (25.5 g/100 g), lignin (1.39 g/100 g), and cellulose (5.31 g/100 g). In terms of physicochemical properties, Tahitian showed the highest water solubility index (33.3 g/100 g), while Tahitian and Moi exhibited the two highest water absorption indices (5.81 g/g and 5.68 g/g, respectively). Regarding functional properties, Tahitian had the highest water absorption capacity (3.48 g/g), and Tahitian and Moi had the two highest oil absorption capacities (3.15 g/g and 2.68 g/g, respectively). Therefore, the flours from these Hawaiian taro varieties possess promising characteristics that could enhance food quality when used as alternative additives in food processing.

Determination of the Nutrient and Toxic Element Content of Wild-Collected and Cultivated Seaweeds from Hawai'i.

For centuries, Hawaiians have gathered seaweed for food, medicine, and ceremonial purposes. Seaweed contains nutrients, but some varieties can accumulate toxic elements. We measured target macrominerals (Na, Mg, P, K, Ca), microminerals (B, V, Mn, Co, Cu, Zn, Mo), and nonessential/toxic elements (As, Sr, Cd, Sn, Hg, Pb, and U) in a sample of wild-collected and cultivated seaweeds from Hawai'i. The samples consisted of brown (Sargassum aquifolium, Sargassum echinocarpum), red (Gracilaria parvispora, Halymenia formosa, Halymenia hawaiiana), and green (Ulva ohnoi) seaweed. Elemental composition was determined by inductively coupled plasma (ICP)-atomic emission spectroscopy and ICP-mass spectrometry (MS). Speciation of As was conducted by using liquid chromatography-ICP-MS. S. echinocarpum per 80 g serving was high in Ca (~37% daily value [DV]), U. ohnoi was high in Mg (~40%DV), H. formosa was high in Fe (~40%DV), and G. parvispora was high in Mn (~128%DV). In this study, the highest amounts of toxic elements were observed in S. aquifolium and S. echinocarpum (27.6 mg inorganic As/kg fdw), G. parvispora (43.3 mg Pb/kg fdw) and H. formosa (46.6 mg Pb/kg fdw). These results indicate that although seaweeds from Hawai'i contain a variety of nutrients, some species can accumulate high amounts of toxic elements.

Selective Detection of Escherichia coli K12 and Staphylococcus aureus in Mixed Bacterial Communities Using a Single-Walled Carbon Nanotube (SWCNT)-Functionalized Electrochemical Immunosensor with Dielectrophoretic Concentration.

An electrochemical immunosensor has been developed for the rapid detection and identification of potentially harmful bacteria in food and environmental samples. This study aimed to fabricate a microwire-based electrochemical immunosensor (MEI sensor) for selective detection of Escherichia coli and Staphylococcus aureus in microbial cocktail samples using dielectrophoresis (DEP)-based cell concentration. A gold-coated tungsten microwire was functionalized by coating polyethylenimine, single-walled carbon nanotube (SWCNT) suspension, streptavidin, biotinylated antibodies, and then bovine serum albumin (BSA) solutions. Double-layered SWCNTs and 5% BSA solution were found to be optimized for enhanced signal enhancement and nonspecific binding barrier. The selective capture of E. coli K12 or S. aureus cells was achieved when the electric field in the bacterial sample solution was generated at a frequency of 3 MHz and 20 Vpp. A linear trend of the change in the electron transfer resistance was observed as E. coli concentrations increased from 5.32 × 102 to 1.30 × 108 CFU/mL (R2 = 0.976). The S. aureus MEI sensor fabricated with the anti-S. aureus antibodies also showed an increase in resistance with concentrations of S. aureus (8.90 × 102-3.45 × 107 CFU/mL) with a correlation of R2 = 0.983. Salmonella typhimurium and Listeria monocytogenes were used to evaluate the specificity of the MEI sensors. The functionalization process developed for the MEI sensor is expected to contribute to the sensitive and selective detection of other harmful microorganisms in food and environmental industries.

Quantitative Determination of the Hydrophobicity of Nanoparticles.

The hydrophobicity of nanoparticles (NPs) is one of the most important physicochemical properties that determines their agglomeration state under various environmental conditions. When studying nano-bio interactions, it is found that the hydrophobicity of NPs plays a predominant role in mediating the biological response and toxicity of the NPs. Although many methods have been developed to qualitatively or quantitatively determine hydrophobicity, there is not yet a scientific consensus on the standard of characterizing the hydrophobicity of NPs. We have developed a novel optical method, called the maximum particle dispersion (MPD), for quantitatively characterizing the hydrophobicity of NPs. The principle of measurement of the MPD method lies in the control of the aggregation state of the NPs via manipulating the van der Waals interactions between NPs across a dispersion liquid. We have scrutinized the mechanism of the MPD method using a combination of dynamic light scattering and atomic force microscopy and further verified the MPD method using a completely independent dye adsorption method. The MPD method demonstrated great promise to be developed into an easy-to-use and cost-effective method for quantitatively characterizing the hydrophobicity of NPs.

Impact of thermal processing on the nutrients, phytochemicals, and metal contaminants in edible algae.

Edible algae products have increasingly become a larger component of diets worldwide. Algae can be a source of essential micronutrients and bioactive phytochemicals, although select varieties also often contain elevated concentrations of heavy metal contaminants. Due to the effects thermal processing of foodstuffs can have on levels of nutrients, phytochemicals, and contaminants, it is important to consider the role processing has on the levels of these components in algae food products. Here, we evaluate the literature covering how different types of processing, including commercial thermal application and in-home preparation, affect constituents such as vitamins, minerals, carotenoids, pigment compounds, and metal contaminants. Overall, the literature suggests that there are optimum processing conditions and specific cooking techniques that can be used to increase retention of important nutritional components while also reducing concentrations of metal contaminants. Although further research is needed on how thermal processing affects individual compounds in algae and their ultimate bioavailability, these data should be taken into consideration in order to inform design of product processing to both increase retention of nutritional components and limit metal contaminants.

Potential health benefits of (poly)phenols derived from fruit and 100% fruit juice.

(Poly)phenol-rich diets have been associated with reduced risk of various diseases. Coffee and tea are typically identified as dietary sources of chlorogenic acid and flavan-3-ols; however, 100% fruit juice greatly contributes to anthocyanin, flavonol, flavan-3-ols, and flavanone intake, making them complementary sources of dietary (poly)phenols. Thus, the aim of this narrative review was to provide an overview of fruit (poly)phenols and their potential health benefits. Fruit (poly)phenols have been associated with several health benefits (eg, reduced risk of cardiovascular disease and neurocognitive benefits). Although perspectives on 100% fruit juice consumption are controversial due to the perception of sugar content, growing evidence supports the role of fruit in whole and 100% juice forms to provide consumer benefits in alignment with dietary guidance. However, differences in (poly)phenol profiles and bioavailability likely exist between whole fruit and 100% fruit juice due to processing and the presence/absence of fiber. Ongoing studies are better defining similarities and differences between whole fruit and 100% fruit juice to elucidate protective mechanisms and align with processing and consumer products.

The Roles of Food Processing in Translation of Dietary Guidance for Whole Grains, Fruits, and Vegetables.

The Dietary Guidelines for Americans (DGA) recommend the consumption of whole grains, fruits, and vegetables as part of a healthy diet. However, current consumption patterns suggest that most Americans are not meeting these recommendations. The challenge remains to align the DGA guidance with the food environment and consumers' expectations for product quality, availability, and affordability. Currently, processed foods play an increasingly important role in American diets. Often characterized as unhealthy, processed foods are contributors to both food and nutritional security. When the alignment of processing strategies with DGA principles exists, achieving DGA goals is more likely, regardless of processing level. In this review, select processing strategies for whole grains, fruits, and vegetables are described to show how DGA principles can guide processing efforts to create healthier products. Although whole grains, supported by industry-wide innovation and guidance, have had some success with consumers, improving intake of fruit and vegetable products remains a challenge. Closing consumption gaps requires new innovations and products aligned with consumer preferences and DGA principles.