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Item Nanodelivery systems of thymoquinone for improving its bioavailability and efficiency in the food and biomedical applications(Elsevier B V, 2025-10-15) Shaddel R; Rashidinejad A; Karimkhani MM; Tarhan O; Jafari SMThymoquinone (TQ), a hydrophobic bioactive constituent of Nigella sativa seeds, has garnered attention for its potential in treating various ailments due to its antioxidative and anti-inflammatory properties. However, TQ's hydrophobicity, instability in varying pH environments, photosensitivity, rapid hepatic metabolism, and low bioavailability present major challenges for its application in pharmaceutical and nutraceutical formulations. Nanotechnology offers innovative nanocarriers that can overcome these limitations. Notable among these are lipid-based nanocarriers (e.g., nano-liposomes, nano-emulsions, niosomes, solid lipid nanoparticles, and nanostructured lipid carriers), biopolymeric systems (e.g., nano-hydrogels, nanofibers, nanotubes, and cyclodextrin inclusion complexes), and inorganic nanocarriers. These delivery systems are designed to enhance TQ's solubility, protect it from degradation, and improve its bioavailability and therapeutic performance. Despite numerous advances, the clinical and industrial translation of these nano-delivery systems remains limited, primarily due to scalability issues, regulatory constraints, and a lack of standardized evaluation protocols for food and biomedical use. This review provides a comprehensive analysis of these nanocarriers, emphasizing their mechanisms for TQ encapsulation, controlled release, and bioaccessibility enhancement. It also highlights current limitations and outlines future directions for their development. Unlike previous reviews, this work offers a comparative evaluation of nanocarrier systems for both food and biomedical applications, addressing their effectiveness, limitations, and readiness for real-world translation. The key takeaway is that among the various approaches, lipid-based and biopolymeric nanocarriers have demonstrated the greatest potential for enhancing TQ delivery, particularly in oral and functional food formulations, as well as targeted cancer therapy, due to their biocompatibility, scalability, and effective release profiles.Item Bioaccessibility and associated concepts: Terminology in the context of in vitro food digestion studies(Elsevier Ltd, 2025-09-01) Grundy MM-L; Deglaire A; Le Feunteun S; Reboul E; Moughan PJ; Wilde PJ; McClements DJ; Marze SIn vitro gastrointestinal models are widely used to study food digestion, in combination with analytical methods to determine the physicochemical and biochemical fate of food compounds. The in vitro bioaccessibility determined with these models is often used as an indicator of the in vivo bioavailability. However, the bioaccessibility concept is not used consistently within the scientific literature, leading to confusion and making it difficult to compare the results from different studies. The aim of this article is to provide standardized definitions of in vitro digestibility and bioaccessibility, detailing the main processes involved, including physical release, solubilization, and biochemical/metabolic reactions. The terminology of complementary cellular, ex vivo, and animal/human in vivo experiments is also given. Application of the in vitro terminology to different nutrients is discussed, including lipids, proteins, carbohydrates, vitamins, and other bioactive compounds. The proposed definitions unify most concepts related to the gastrointestinal fate of ingested food compounds.Item Whole-body protein kinetic models to quantify the anabolic response to dietary protein consumption(Elsevier Ltd d on behalf of European Society for Clinical Nutrition and Metabolism, 2021-04) Wolfe RR; Kim I-Y; Church DD; Moughan PJ; Park S; Ferrando AADetermination of whole body rates of protein synthesis, breakdown and net balance in human subjects still has an important role in nutrition research. Quantifying the anabolic response to dietary protein intake is a particularly important application. There are different models with which to accomplish this goal, each with advantages and limitations. The nitrogen (N)-flux method in which tracer is given orally has distinct advantages in terms of lack of invasiveness. In addition, the calculated results include all aspects of whole-body protein synthesis and breakdown. However, the prolonged timeframe of the method eliminates the possibility of the “pre-post” experimental design whereby each subject serves as their own control in the evaluation of the response to a meal. Models based on the primed-constant infusion of an essential amino acid (EAA) tracer enable the determination of baseline whole-body protein kinetics within 2 h, and can quantify a dynamic change from the basal state. The greatest challenge when using an EAA model is distinguishing exogenous and endogenous sources of the tracee in the blood. One approach is to use an intrinsically-labeled protein. This method has the advantage that the exogenous tracee is clearly distinguished from endogenous tracee. On the other hand, the intrinsically-labeled protein method suffers from unmeasured dilution that is likely to cause the systematic underestimation of the rate of appearance of exogenous tracee and thus overestimate the rate of whole-body protein breakdown. Alternatively, the “bioavailability” approach estimates the contribution of exogenous tracee to the peripheral circulation from the amount of tracee ingested, the true ileal digestibility of the tracee, and the irreversible loss of tracee prior to entry into the peripheral circulation. Errors in assumed values with the bioavailability method can potentially be significant, but are not likely to result in the systematic over- or under-estimations of rates of whole-body protein synthesis and breakdown. The optimal method depends on the degree of uncertainty regarding required assumptions in a particular circumstance. With all methods, it is advisable to calculate upper and lower bounds of whole body protein kinetics, in accord with reasonable maximal and minimal assumed values. Simultaneous use of two methods requiring different assumptions can also serve to confirm the validity of single approach.Item The role of holistic nutritional properties of diets in the assessment of food system and dietary sustainability(Taylor and Francis Group, 2023) Dave LA; Hodgkinson SM; Roy NC; Smith NW; McNabb WCAdvancing sustainable diets for nutrition security and sustainable development necessitates clear nutrition metrics for measuring nutritional quality of diets. Food composition, nutrient requirements, and dietary intake are among the most common nutrition metrics used in the current assessment of sustainable diets. Broadly, most studies in the area classify animal-source foods (ASF) as having a substantially higher environmental footprint in comparison to plant-source foods (PSF). As a result, much of the current dietary advice promulgates diets containing higher proportions of PSF. However, this generalization is misleading since most of these studies do not distinguish between the gross and bioavailable nutrient fractions in mixed human diets. The bioavailability of essential nutrients including β-carotene, vitamin B-12, iron, zinc, calcium, and indispensable amino acids varies greatly across different diets. The failure to consider bioavailability in sustainability measurements undermines the complementary role that ASF play in achieving nutrition security in vulnerable populations. This article critically reviews the scientific evidence on the holistic nutritional quality of diets and identifies methodological problems that exist in the way the nutritional quality of diets is measured. Finally, we discuss the importance of developing nutrient bioavailability as a requisite nutrition metric to contextualize the environmental impacts of different diets.Item Recent advances in the conjugation approaches for enhancing the bioavailability of polyphenols(Elsevier Ltd, 2024-01) Sahraeian S; Rashidinejad A; Golmakani M-TIn recent years, the consumption of functional foods containing health-beneficial ingredients has become increasingly popular. Polyphenols are among the most important functional and bioactive molecules found in a variety of fresh produce and food products. However, the limited solubility of most polyphenols in water can significantly affect their bioavailability, thereby reducing their potential health benefits. To overcome this limitation, various approaches have been explored, including molecular enhancers, nanoparticles, encapsulation systems, and conjugation methods. In this review, we focus on recent advances in conjugation methods for enhancing the bioavailability of polyphenols. We provide a concise overview of the types of polyphenols and bioavailability determination methods and, subsequently, discuss the concept of conjugation methods, including different synthesizing methods, confirmation procedures, and the effects of conjugation on polysaccharides and polyphenols. Overall, this review provides a comprehensive update on recent advances in conjugation methods that can be used to improve the bioavailability of polyphenols and highlights the potential of these approaches to enhance the health benefits of polyphenol-rich foods.Item Manipulating soil bioavailable copper as an innovative nitrate leaching mitigating strategy in New Zealand pastoral soils : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Soil Science, School of Agriculture and Environment, College of Sciences, Massey University, Palmerston North, New Zealand(Massey University, 2023) Matse, Dumsane ThembaUrine patches are the primary sources of nitrate (NO₃⁻ -N) leaching from pastoral dairy farms. Since NO₃⁻ -N is the product of nitrification, a clear understanding of the nitrification process is a vital step toward the development of effective and efficient mitigation approaches. The first step of ammonia (NH₄⁺) oxidation to hydroxylamine (NH₂OH) is catalyzed by the ammonia monooxygenase enzyme (AMO), and copper (Cu) is a co-factor in the activity of the AMO enzyme. Therefore, manipulating Cu bioavailability through the application of Cu-complexing organic compounds such as calcium lignosulphonate (LS) and co-poly acrylic-maleic acid (PA-MA) to soil could influence AMO activity and consequently limit the nitrification rate in soil. There are no published studies that have examined the effect of bioavailable Cu concentration changes on nitrification rate, ammonia-oxidizing bacteria (AOB) and archaea (AOA), and NO₃⁻ -N leaching. The overall aim of this thesis is to determine the significance of bioavailable Cu in the nitrification process in the context of developing novel Cu-complexing organic compounds to inhibit nitrification rate in pastoral soils. A soil incubation study was conducted to characterize the relationship between changes in soil bioavailable Cu concentration and nitrification rate. This study was conducted using three pastoral soils (Pumice, Pallic, and Recent soils) spiked with five Cu levels (0.1, 0.3, 0.5, 1, and 3 mg kg⁻¹). Treatments of Cu-complexing compounds were separately applied to each Cu level. The treatments were urea applied at 300 mg N kg⁻¹, urea + LS at 120 mg kg⁻¹, and urea + PA-MA at 10 mg kg⁻¹. Results show that increasing the added Cu concentration from 0.1 to 3 mg kg⁻¹ increased nitrification rate by 35, 22, and 33% in the Pumice, Pallic, and Recent soils, respectively. Application of LS and PA-MA significantly (P ˂ 0.05) decreased nitrification rate with the mean reduction being 59 and 56%, 32 and 26%, and 39 and 38% in the Pumice, Pallic, and Recent soils, respectively at Day 8 relative to the urea-only treatment. To further extend knowledge of the relationship between bioavailable Cu and the key nitrifying microorganisms in soils, a greenhouse-based pot trial using three soils (Pumice, Pallic, and Recent soils) planted with ryegrass and treated with synthetic urine applied at 300 kg N ha⁻¹ and three levels of Cu (0, 1, 10, 100 mg added Cu kg⁻¹) was established. Results show that AOB amoA gene abundance increased as a function of increasing added Cu from 1 to 10 mg kg⁻¹ but was inhibited at 100 mg added Cu kg⁻¹ in both Pallic and Recent soils. The effect of bioavailable Cu was not apparent in the Pumice soil. The increase in AOB amoA gene abundance positively correlated with nitrification rate in both the Pallic (r = 0.982, P < 0.01) and Recent soil (r = 0.943, P < 0.01) but not in the Pumice soil. There was no effect of increasing Cu concentration on AOA amoA gene abundance in all three soils. Results from both incubation and greenhouse pot trials provide strong evidence that Cu is an important trace element in the nitrification process and reducing Cu can reduce nitrification in soil. However, in order to definitively quantify this treatment effect, further field studies were necessary. Therefore, a field lysimeter study was conducted using Pumice soil (Manawatu climate) and Pallic soil (Canterbury climate). The following treatments were investigated to reduce NO₃⁻ -N leaching during late-autumn application; urine only at 600 kg N ha⁻¹, urine + PA-MA at 10 kg ha⁻¹, urine + LS at 120 kg ha⁻¹, urine + a split-application of calcium lignosulphonate (2LS at same rate, initial and after a month of first application), and urine + ProGibb SG (GA at 80 g ha⁻¹) + LS (GA + LS). Another set of treatment applications, urine only, urine + GA only, and urine + GA + LS, were applied mid-winter to both soils. The GA was applied to improve the effectiveness of these organic compounds during climatic periods of poor plant growth. Results showed that there was no significant reduction in mineral N leaching associated with the late-autumn application of both PA-MA and LS for the Pumice or Pallic soils. However, the application of 2LS reduced mineral N leaching by 16 and 11% in Pumice and Pallic soils, respectively, relative to urine-only. The late-autumn inclusion of GA increased the effectiveness of LS in both soils. This was confirmed by a significant reduction of mineral N leaching by 35% from both Pumice and Pallic soils. Mid-winter application of GA + LS significantly reduced mineral N leaching only in the Pumice soil (by 20%) but not in the Pallic soil relative to urine-only. In both late-autumn and mid-winter treatments application of the different Cu-complexing treatments did not have negative effects on pasture dry matter yield in either Pumice or Pallic soils. In this lysimeter study, the mechanistic effect of PA-MA and LS on reducing bioavailable, nitrification rate and AOB/AOA amoA gene abundance was not investigated. A second field lysimeter experiment was established using the Recent soil in Manawatu to explore the mechanism of Cu manipulation through the application of LS and PA-MA on nitrification rate, AOB/AOA amoA gene abundance, and mineral N leaching. The effect of combining organic inhibitors with GA on reducing mineral N leaching was also investigated. This study evaluated the same treatments used in the first lysimeter study and applications were again conducted at two different seasonal periods (late-autumn and mid-winter). The results showed that the effect of PA-MA and 2LS on bioavailable Cu corresponded with a reduction in nitrification rate and AOB amoA gene abundance. The effect of PA-MA and 2LS was associated with reduced mineral N leaching by values of 16 and 30%, respectively, relative to urine-only. The reduction in mineral N leaching induced by PA-MA and 2LS increased N uptake by 25 and 7.8% and herbage DM yield by factors of 11 and 8%, respectively, relative to the urine-only. The LS treatment did not induce a significant change of either bioavailable Cu or nitrification rate which corresponded to no significant effect on mineral N leaching. The late-autumn combination of GA + LS reduced mineral N leaching by 19% relative to urine-only, but there was no significant difference in mineral N leaching observed for the mid-winter application relative to urine-only. The overall results of this research show that bioavailable Cu is a vital trace element in the nitrification process and for AOB functioning in soil. Therefore, reduction in bioavailable Cu through the application of Cu-complexing compounds can inhibit nitrification. In this doctoral study, the application of Cu-complexing compounds (LS and PA-MA) showed potential to inhibit nitrification rate and subsequently reduce mineral N leaching in pastoral systems, but their efficacy depends on soil characteristics. Future work is recommended to investigate the effect of LS and PA-MA application on nitrous oxide emissions. Further research is recommended to investigate the short and long terms effects of these treatments on non-target soil microbiota.