Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Development of a validated efficient HPLC-DAD analysis for assessing polyphenol transformation during black tea processing(Elsevier Inc, 2025-12-01) Muthulingam P; Popovich DG; Nimal Punyasiri PA; Nanayakkara CM; Mesarich CH; Rashidinejad ATea (Camellia sinensis) is valued for its polyphenolic compounds, which define its sensory and health attributes. Accurate quantification across processing stages is hindered by analytical and extraction challenges. We developed and validated a rapid high-performance liquid chromatography with diode array detection (HPLC-DAD) method for simultaneous analysis of 12 key constituents - gallic acid, theobromine, caffeine, (+)-catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG), theaflavin (TF), theaflavin-3-gallate (TF3G), theaflavin-3′-gallate (TF3’G), theaflavin-3,3′-digallate (TF3–3’G), in green and black tea. The method achieved superior linearity (r² > 0.9995), high sensitivity (LOD: 0.03–1.68 µg/mL), strong precision (RSD < 4.68 %), and high recovery, while also resolving co-elution with a 40-min runtime. Extraction was optimized using ultrasonication with 70 % methanol, which outperformed hot water and ISO-standard methods. Applied to black tea processing, the method revealed a 79.1 % reduction in catechins, post-rolling theaflavin peaks, and dynamic fluctuations in gallic acid, caffeine, and theobromine. These changes were associated with enzymatic oxidation, leaching, and cultivar effects. The validated HPLC-DAD method provides a robust tool for tea polyphenol profiling and enables improved understanding of processing-induced transformations. It holds potential for use in quality control, nutritional labeling, and functional food research in tea and other polyphenol-rich systems.Item Biopolymer-polyphenol conjugates: Novel multifunctional materials for active packaging(Elsevier B V, 2024-11) Sahraeian S; Abdollahi B; Rashidinejad AThe development of natural active packaging materials and coatings presents a promising alternative to petroleum-based packaging solutions. These materials are engineered by incorporating functional ingredients with preservative capabilities. Concurrently, research has highlighted the diverse physicochemical, functional, and health-promoting properties of protein-polyphenol, polysaccharide-polyphenol, and protein-polysaccharide-polyphenol conjugates within various food formulations. However, a critical gap exists regarding the exploration of these biopolymers as active packaging materials. In contrast to conventional approaches for developing active packaging materials, this review presents a novel perspective by focusing on biopolymer-polyphenol conjugates. In this work, we delve into the realm of active packaging materials and coatings constructed from these conjugates, highlighting their potential as multifunctional active components in food packaging and preservation. This review comprehensively investigates the physicochemical properties, functionalities, and health-promoting activities associated with biopolymer-polyphenol conjugates. Their emulsification, antioxidant, and antimicrobial activities, coupled with enhancements in mechanical strength and permeability properties, contribute to their multifunctional nature. Furthermore, we explore the potential advantages and limitations of utilizing these conjugates in active packaging applications. Finally, the review concludes by proposing crucial research avenues for further exploration of biopolymer-polyphenol conjugates within the domain of active food packaging.Item Assessment of Various Food Proteins as Structural Materials for Delivery of Hydrophobic Polyphenols Using a Novel Co-Precipitation Method(MDPI (Basel, Switzerland), 2023-04-19) Rashidinejad A; Nieuwkoop M; Singh H; Jameson GB; Papetti AIn this study, sodium caseinate (NaCas), soy protein isolate (SPI), and whey protein isolate (WPI) were used as structural materials for the delivery of rutin, naringenin, curcumin, hesperidin, and catechin. For each polyphenol, the protein solution was brought to alkaline pH, and then the polyphenol and trehalose (as a cryo-protectant) were added. The mixtures were later acidified, and the co-precipitated products were lyophilized. Regardless of the type of protein used, the co-precipitation method exhibited relatively high entrapment efficiency and loading capacity for all five polyphenols. Several structural changes were seen in the scanning electron micrographs of all polyphenol-protein co-precipitates. This included a significant decrease in the crystallinity of the polyphenols, which was confirmed by X-ray diffraction analysis, where amorphous structures of rutin, naringenin, curcumin, hesperidin, and catechin were revealed after the treatment. Both the dispersibility and solubility of the lyophilized powders in water were improved dramatically (in some cases, >10-fold) after the treatment, with further improvements observed in these properties for the powders containing trehalose. Depending on the chemical structure and hydrophobicity of the tested polyphenols, there were differences observed in the degree and extent of the effect of the protein on different properties of the polyphenols. Overall, the findings of this study demonstrated that NaCas, WPI, and SPI can be used for the development of an efficient delivery system for hydrophobic polyphenols, which in turn can be incorporated into various functional foods or used as supplements in the nutraceutical industry.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 Exploring efficient extraction methods: Bioactive compounds and antioxidant properties from New Zealand damson plums(Elsevier Ltd, 2023-10) Xia P; Ahmmed MK; Rashidinejad AThe study determined the best extraction method for phenolic compounds (rutin, catechin, epicatechin, naringenin, neochlorogenic acid, and rosmarinic acid) in the New Zealand damson plums. Accelerated solvent extraction (ASE) using ethanol and water was used to evaluate the solvent efficacy. Further comparisons were made among ASE, ultrasound-assisted extraction (UAE), enzyme-assisted extraction (EAE), and a combined method (E + UAE) using water as the solvent. The findings showed that ASE for 40 min was the most effective method for extracting phenolic compounds (1.76 mg gallic acid equivalent/g) compared to other methods (UAE = 1.17, EAE = 1.3, and E + UAE = 1.45 mg/g). The ASE method also resulted in an extract with a higher antioxidant activity than other methods. The extraction time over 40 min decreased the yield regardless of the solvent used. Therefore, the ASE extraction method for 40 min is recommended as the best method for extraction of phenolic compounds from the New Zealand damson plums.