Sunan Wang’s research while affiliated with University of Auckland and other places

Abstract Cost‐effective and under‐exploited plant species as functional food ingredients represent alternatives to chemicals with safety concerns and potent toxicity. Staghorn sumac (Rhus typhina) is considered a good source of natural polyphenols, which can be introduced into food products to carry out some specific technological functions (e.g., antioxidation and preservation). However, sumac fruit as a spice is under‐explored for its diversified uses in various food products as a novel functional ingredient. This study explored the technological feasibility and sensory acceptability of two representative sumac‐fortified food systems, namely Cheddar cheese and ground beef. Extracts of sumac (0.5%−5%) dose‐dependently increased the total phenolic and anthocyanin contents, while reducing thiobarbituric acid reactive substance (up to 46%), total plate counts of bacteria (up to 4.5 log colony‐forming units [CFU]/g) and pH of the cheese. In fresh ground beef, sumac extract at concentrations of 1%−5% was effective in reducing the total aerobic counts of Escherichia coli inoculated fresh ground beef by 0.16−1.14 log CFU/g, while improving meat color and oxidative stability during a storage period of 7 days at 4°C. Phytochemical profiling by high‐performance liquid chromatography showed the presence of gallic acid, caffeic acid, ellagic acid, quercetin and anthocyanins in the sumac extracts. These compounds were possibly responsible for the antimicrobial and antioxidant activities in the evaluated food systems. Sensory acceptability of Cheddar cheese or cooked beef meatballs with sumac extract addition (0.5%−3%) were similar to their respective controls. This study provides a feasible approach to satisfy health‐conscious consumers who favor a natural multifunctional ingredient to preserve food products.

Pu-erh tea is post-fermented sun-dried tea leaves of Camellia sinensis (Linn.) var. assamica (Masters) Kitamura plant, native to Yunnan, China. Pu-erh tea is a highly prized commodity with unique aroma and taste and multiple health effects. This review overviews the chemical constituents, tentative bioactive compounds and their mechanisms responsible for bioactivities of Pu-erh tea. The bioactivities include antioxidative, antimutagenic, antimicrobial, laxative and neuroprotective activities, and controlling or preventing hypercholesterolemia, hyperglycemia, obesity, diabetes, osteoporosis and Alzheimer’s disease. Limited human trials hardly convince therapeutic efficiency of Pu-erh tea. Raw and ripened Pu-erh tea possess their respective sensory characteristics, chemical and microbial diversities. Chemical and biological differences between Pu-erh and other tea types could be explained by different extents of their respective processing-induced compound transformations. Undesirable heavy metals, mycotoxins and other biocontaminants detected in Pu-erh tea relate to growing conditions of tea plants, processing and storage conditions. Chemistry- and nutrition-derived mechanisms for tea pricing are lacking. Decontamination strategies and future studies for quality improvement are recommended.

Cocoa (Theobroma cacao L.) is widely cultivated in tropical countries. The cocoa beans are a popular ingredient of confectionery. Cocoa beans contain various chemicals that contribute to their bioactivity and nutritional properties. There has been increasing interest in developing cocoa beans for “healthy” food products. Cocoa beans have special combination of nutrients such as lipids, carbohydrates, proteins and other compounds of biological activities. The bioactive phytochemicals include methylxanthines, polyphenols, biogenic amines, melanoidins, isoprostanoids and oxalates. These phytochemicals of cocoa are related to various in vivo and in vitro biological activities such as antioxidation, anti-cancer, anti-microbial, anti-inflammation, anti-diabetes, cardiovascular protection, physical improvement, anti-photoaging, anti-depression and blood glucose regulation. The potential of bioactive compounds in cocoa remains to be maximized for food and nutritional applications. The current processing technology promotes the degradation of beneficial bioactive compounds, while maximizing the flavors and its precursors. It is not optimized for the utilization of cocoa beans for “healthy” product formulations. Modifications of the current processing line and non-conventional processing are needed to better preserve and utilize the beneficial bioactive compounds in cocoa beans.

Kiwifruit (Actinidia spp.) is a commercially important fruit crop. Various species and cultivars, non-fruit plant parts, and agricultural and processing wastes are underutilized. A broad-scoped review of kiwifruit guides further innovative applications. Different kiwifruit varieties and edible and nonedible parts varied in dietary nutrients including polyphenols, vitamins, dietary fiber, and functional ingredients, such as starch and protease and bioactive phytochemicals. Kiwifruits exhibit antioxidative, antiproliferative, antiinflammatory, antimicrobial, antihypertensive, antihypercholesterolemic, neuroprotective, antiobese properties and promote gut health. Clinically significant effects of kiwifruit on prevention and/or treatment of major chronic diseases are not yet evident. Varieties and plant parts, extraction, analytical and processing methods affect the physicochemical and biological properties of kiwifruit-derived ingredients. Allergens, mycotoxins, pesticides and heavy metals are the chemical hazards of kiwifruits. Future research should focus on sustainable uses of underutilized resources as functional ingredients, bioactive compound purification, composition-activity relationships, and physiological mechanisms and clinical significance of kiwifruits.

Adulteration of high-quality meat with their cheaper counterparts can be minimized by rapid and reliable methods for detecting meat species. Here an isothermal cross-primer amplification (CPA) technique combined with colloidal gold nucleic acid test strips (CPA strips) was developed to differentiate cow, sheep, arctic fox, and pig meat. A simple primer design for multiplex differentiation using a universal single-labeled CPA primer system and four detection-level species-specific labeling primers were analyzed by colloidal gold-based test strip assay. Moreover, simultaneous detection of fox and pig meat on a double-test line strip was feasible. The CPA strip assay indicated a lower amounts sensitivity of 0.3 ng DNA when one targeted species was tested and a detection limit of 1% when arctic fox meat was detected in the meat mixtures. Using a minimal set of primers, this study provides a promising tool for detecting the species of different types of meat using a constant temperature amplification technology.

Background Tamarillo (Solanum betaceum) is native to South America and is cultivated in several other parts of the world for its valued fruit. The fruit has therapeutic and nutritional properties that can satisfy the demands from health-conscious consumers. There has been increasing interest in using tamarillo for consumption and food and non-food product formulations. Overall, tamarillo is an underutilized, sustainable fruit crop with great potential for value-added products. Scope and approach This review summarizes the composition of nutritional components and biological properties of tamarillo. The chemical and biological properties of tamarillo are compared to those of common fruits and vegetables. Food and other uses of tamarillo are described. Innovative methods for the development of tamarillo-based products are suggested to maximize the potential of this fruit. Key findings and conclusions Tamarillo has a range of nutrients including dietary fibers, polyphenols, vitamins C, A, B, and E, carotenoids, potassium and iron. Health effects of tamarillo included antioxidative, antiproliferative, antinociceptive, antiinflammatory, allergenicity, and anti-obese properties. These health effects have been tentatively correlated to certain phytochemicals (e.g., non-starch polysaccharides, carotenoids, and anthocyanins). The properties of tamarillo-derived ingredients mainly depended on the cultivar and origin, plant parts, extraction conditions and analytical procedures. Research is needed to explore the composition-activity relationships and mechanisms underlying a biological activity. An array of tamarillo based products have been developed. Overall, tamarillo is a promising “new” fruit crop with potential to be exploited as a source of “healthy” products.

Maca (Lepidium meyenii Walpers) has emerged as a popular functional plant food due to various claimed health effects. This review details the major (i.e., starch, dietary fiber, and protein) and minor constituents (i.e., minerals, non-starch polysaccharides, polyphenols (flavonolignans), macaenes, macamides, glucosinolates, and alkaloids) of maca (root and aerial parts). Diverse health effects of maca are also summarized. Various bioactivities of maca include enhanced reproductive health, antifatigue, antioxidation, neuroprotection, antimicrobial activity, anticancer, hepatoprotection, immunomodulation, and improving skin health and digestive system's function. Plant genetics, botanical parts, processing, extraction, and experimental protocols represent the major factors affecting the chemical composition, physicochemical attributes, and health effects of maca-based products. However, clinical studies to support the claimed health effects of maca and related mechanisms appear to be lacking. Product innovation and diversification in food and non-food utilization of different parts of maca to maximize the value perceptions are suggested.

Sacha inchi (Plukenetia volubilis L.) is native to the Peruvian Amazon and is recognised in other parts of the world as a sustainable crop with viable commercial applications. In recent years, there has been growing interest in developing the sacha inchi plant as a novel source of oil rich in unsaturated fatty acids. This review presents information on the major and minor chemical components, health effects and utilization of different parts (seeds, seed shells and leaves) of this plant. In particular, the physicochemical properties and oxidative stability of sacha inchi seed oil are described. The whole sacha inchi plant has been utilized to generate nutritional, cosmetic and pharmaceutical products with the goal to maximize its economic value. The sacha inchi plant may become a valuable resource for high value-added compounds used in many diverse food and non-food products.

Lactic acid fermentation represents novel method to produce bioactive functional ingredients, including polysaccharides. In this work, a selected lactic acid bacteria strain NCU116 was used to ferment Asparagus officinalis (asparagus) pulps. Two polysaccharides were subsequently separated from both unprocessed and fermented asparagus pulps, namely asparagus polysaccharide (AOP) and fermented-AOP (F-AOP). The physicochemical and bioactive properties of AOP and F-AOP were characterized and investigated. High-performance anion-exchange chromatography showed that fermentation increased the proportions of rhamnose, galacturonic acid, and glucuronic acid in polysaccharides by 46.70, 114.09 and 12.75‰, respectively. High-performance size-exclusion chromatography revealed that fermentation decreased the average molecular weight from 181.3 kDa (AOP) to 152.8 kDa (F-AOP). Moreover, the fermentation reduced the particle size and changed the rheology property. In vitro, F-AOP displayed superior free radical scavenging properties than AOP, using DPPH, hydroxyl and superoxide anion radical scavenging assays. In vivo, F-AOP administration dose-dependently promoted a gradual shift from Th17-dominant acute inflammatory response (IL-17 and RORγt) to Th1-dominant defensive immune response (IFN-γ and T-bet). These results indicated that the lactobacillus plantarum NCU116 fermentation was practical and useful to obtain promising bioactive polysaccharides.