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The Department of Wine, Food and Molecular Biosciences covers course areas including animal and plant science, biochemistry, food science, horticulture, microbiology, sensory science, viticulture and wine science.
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Item Restricted Investigating the preparation of hemp-protein isolate (HPI)(2024-07) Wu, Gaosheng; Kumar, Lokesh; Morton, James; Lee, HannahThe aim of this research is to investigate the preparation of hempprotein isolate (HPI) and its subsequent hydrolysis using 0.5%bacterial protease and 2% pepsin protease in order to address HPI's low solubility, resulting in the production of hemp proteinhydrolysates (HPH). Samples were extracted minutes,showing identical degrees of hydrolysis. Hemp protein hydrolyzed with bacterial protease (HPHB) enhanced oil absorption capacity andemulsifying capacity, while hemp protein hydrolyzed with pepsin (HPHP)demonstrated an increase in water absorption capacity. In addition,the effects of varying HPH concentrations on the functional and nutritional properties of corn starches were explored. The study involved mixing two types of HPH, with concentrations of 10% and 20%,respectively, with normal corn starch (NCS), waxy corn starch (WCS),and high amylose corn starch (HACS). The significant decrease in RDS values was around 22% with 20% HPHP in HACS. The highest increase in RSvalues was about 10% with 10%HPHB in WCS. 20% HPHP exhibited the highest antioxidant activity among the three different amylose content starches and 20%HPH exhibited a favorable amino acid profile characterized by HPLC analysis. This study contributes to a deeper understanding of the interactions between starch-protein hydrolysates and holds promise for the development of healthier, more sustainable,and innovative foods.Item Open Access Proximate composition, peptide characterization and bioactive properties of faba bean blanching water(Elsevier Ltd., 2025-01) Feng, Z; Morton, James; Maes, E; Kumar, Lokesh; Serventi, LucaFaba bean (Vicia faba L.) offers a rich nutritional profile with high protein content and abundant vitamins and minerals. Processing of faba beans for freezing requires blanching, yielding liluva (legume processing water), possibly containing leached macronutrients, with potential for upcycling. Past evidence has shown that legume processing water may be high in protein. Peptides generated from faba bean proteins during processing have been shown to have bioactivity and can, for example, inhibit HMG-CoA reductase. HMG-CoA reductase is rate-limiting in the biosynthesis of cholesterols and high cholesterol increases the risk of cardiovascular diseases. Thus, this study examined the composition of legume blanching water, analysed the peptides resulting from in vitro digestion and assayed HMG-CoA reductase inhibitory activity of liluva from faba beans sourced from two farms in Canterbury, New Zealand. Results showed that the blanching water contained around 1.7 g/100 mL solid content. These solids were approximately 30 % protein, 12 % water-soluble carbohydrates, 4 % dietary fibre, and 0.17 % ash. Mineral analysis showed high levels of potassium in macro minerals and zinc in trace minerals. Free amino acid analysis revealed high levels of arginine, alanine, asparagine, and glutamic acid, and low levels of methionine and tryptophan. Mass spectrometry analysis identified 111 and 72 endogenous peptides in farm 1 and 2 raw samples, respectively. Most of these peptides were derived from tripeptidyl-peptidase II and subtilisin-like protease. To understand potential bioactivity of these peptides, peptides were also analyzed after in vitro digestion. The resulting identified peptides indicated in silico predicted bioactivities such as anti-thrombotic, antioxidative, ACE dipeptidyl peptidase −III and −IV inhibition and HMG-CoA reductase inhibition activities. Further validation of the faba bean blanching water after in vitro digestion demonstrated approximately 67 % inhibition of HMG-CoA reductase activity, suggesting potential hypocholesterolemic properties. These findings suggest that faba bean blanching water may serve as a sustainable and functional ingredient with potential cholesterol-lowering effects in food production.Item Open Access Dietary bioactive compounds trigger distinct epigenetic and metabolic reprogramming in Lactobacillus acidophilus(Cold Springs Harbor Laboratory, 2024-08-18) Kong, Yanzhuo; Adejoro, Damola; Wescombe, Philip A; Winefield, Christopher; On, Stephen; Mitchell, Nadia; Subbaraj, Arvind; Saunders, Andrew; Maes, Evelyne; Chelikani, VenkataLactobacillus acidophilus ATCC 4356 (LA), a key probiotic in the human gut microbiota, offers several health benefits. While dietary bioactive compounds are known to influence gut microbiota, their specific mechanisms remain unclear. This study investigated how certain dietary bioactive compounds impact LA gene expression and metabolism. Results showed each compound produces unique transcriptional, metabolic, proteomic, and epigenetic profiles in LA. Notably, dietary compounds altered the epigenetic landscape through N4-methylcytosine (4mC) modification, a relatively underexplored form of methyl modification that may play a role in regulating gene transcription. For instance, genistein treatment up-regulated 76 genes and the down-regulated 130 genes in LA. A gene involved in mucus-binding proteins, crucial for bacterial adhesion, was up-regulated 38-fold, likely due to 4mC modifications. Additionally, the gene coding for the melibiose operon regulatory protein increased 78-fold, enhancing melibiose (a prebiotic) production with genistein, but only 1.1-fold with sodium butyrate. This study highlights the potential of dietary compounds for microbial metabolic engineering, offering a non-GMO method for modulating bacterial performance and other biotechnology applications.Item Restricted A gastrointestinal parasite infection model for chronic stress in livestock and its impact on meat quality(ACK 2024, 2024-11-13) Lee, Hannah; Morton, JamesLivestock stressors are known to have an impact on both animal welfare and meat quality. As a model of acute stress, we have previously demonstrated the impact of pre-slaughter simulated mustering on several important meat quality markers in lamb, including high pH [1, 2]. To examine a chronic stressor in livestock, we have adapted a model of a sub-clinical infection with gastrointestinal nematode(GIN) parasite infection in sheep. Six month old ram lambs were challenged with a mixed infection of Trichostrongylus colubriformis and Teladorsagia circumcincta (Treatment group, n=6), which are common gastrointestinal parasites frequently encountered in pasture, and compared with those without parasites (Control, n=6) (AEC2023-71). The goal is to understand how parasite infection can impact on inflammatory response as a proxy for animal welfare, along with determining if parasite infection has an impact on meat quality markers. We will also use an emerging metabolomics method, rapid evaporative ionisation mass spectrometry, to provide complementary analytical information on changes to organ and meat metabolite and lipid composition. This data will contribute towards defining and designing further investigations on chronic stressors in livestock. In future, characterised biomarkers of stressors could be used for enhancing animal welfare and confirm the relationship between minimising pre-slaughter stressors and improving the consistency of meat quality.Item Open Access Peptidomic analysis of anionic oat intestinal peptides(2023-07-04) Gong, Xi; Lee, Hannah; Brennan, Margaret; Middleditch, Martin; Morton, JamesMany studies have focused in recent years on the functional and nutritional properties of proteins in cereal and the bran and the bioactive attributes of peptides derived from these proteins. In vitro digestion model in combination with anion exchange chromatography isolates the cereal anionic intestinal peptides which, unlike cereal hydrophobic peptides, has not been proven to strongly relate to the bioactivity of peptides. The aim of my PhD project is to identify the bioactive anionic peptides derived from the storage protein of cereal bran and to assess their bioactivity. The protein was extracted from oat bran, wheat bran and barley and was then subjected to in vitro digestion model. The intestinal digesta of oat bran protein showed highest overall antioxidant and ACE inhibitory activity and was fractionated by anion exchange chromatography, and the fractions of which with highest antioxidant and ACE inhibitory activity were selected for sequencing by R-HPLC-MS/MS. The peptides in the fraction candidates were identified. In addition, the most abundant peptides in the fraction candidates were identified and the relation of those abundant peptides to bioactivity was evaluated. For future perspective, the ACE inhibitory peptide candidates will be analysed by molecular docking. The peptide will be selected for synthesis and assayed to confirm the discovery of the novel peptides. Meanwhile, it is interesting to bring the novel peptides to cell-line works and in vivo.Item Restricted Design and analysis of novel 3D printed foods with re-purposed animal and plant proteins(2023-07-03) Peddisetti, Sahiti; Lee, Hannah; Bentley, Kelly-Anne; Pope, Isobel; Hampton, Jessica; Kaur, Lovedeep; Singh, Jaspreet; Morton, JamesFood Transition 2050 describes the need for New Zealand to diversify its food products. This has led to an increased interest in evaluating new food applications for animal, plant, fungal and microbial proteins. One of the approaches to increase available protein is to reduce food wastage and fully utilize existing animal and plant-based proteins by improving the functional and nutritional value of side streams from the food industry. Often these have either poor texture or visual appeal. 3D food printing technology offers the opportunity to turn these side streams into complex shaped foods with increased functional and nutraceutical value. With the insights on 3D food printing technology and the newly installed in Lincoln University, The current project uses 3D Foodini food printers (manufactured by Natural Machines) to develop the tools and prototype processes that will allow the industry to gain greater value from the NZ resource base by producing new-to-NZ protein ingredients and foods. Our team has successfully established animal protein based (meat or dairy), pea protein based and hybrid (peameat; pea-dairy; pea-dairy-meat) 3D printed foods, and then determined their textural and rheological properties of these 3D printed protein constructs. These attractive 3D printed soft-textured protein-rich products will be particularly useful to people with special dietary requirements like dysphagia and geriatrics.Item Restricted The effect of farmyard stress on meat quality: A model for predictive biomarkers of meat pH(2023) Lee, Hannah; Ross, Alastair; Morton, JamesBackground/Objectivs: High pH meat is frequently associated with poor shelf-life and eating quality, and pH is a commonly used marker for meat quality. Early detection of high pH lamb is desirable and can improve meat quality control. Due to the variability in the occurrence of high pH at meat processing plants in New Zealand, there is a need for reproducible models that allow the study of abnormal pH in meat. We devised a pilot trial using standardised farmyard stress to produce high pH meat. Method: This experiment compared lambs exposed to some of the normal pre-slaughter stress factors within a New Zealand pastoral system with a control group with minimal pre-slaughter stress. It used two groups of 10 lambs, held in the pasture paddock next to the abattoir. The 10 “low stress” animals were kept quietly in pens prior to slaughter while the second group of 10 animals were exercised by moving with a dog for 5-10 minutes every hour for 4 hours prior to slaughter (“moderate exercise stress”). Rapid metabolomics (rapid evaporative ionisation mass spectrometry, REIMS) analyses were carried out on the immediate post-slaughter samples. The carcasses were aged and meat quality measurements were taken at different post mortem time points: pH (at 1.5 h, 24 h), colour (at 4 days), cooking loss and shear force (at 7/8 days). Results: The pH declined significantly over the 24 h post-slaughter in all muscles. At 1.5 h post-mortem, there was no significant difference in the average pH of muscles among non-exercised (pH 6.650, N=100) and exercised groups (pH 6.683, N=99). When the pH of two different fibre types was compared as an early sign of pH response to pre-slaughter exercise stress, the slow/oxidative muscle types had significantly higher pH than the same muscle types from non-exercised group (p=0.011). This was not seen in fast/glycolytic fibre muscles. At 24 h post-mortem muscles, the pH of the muscles from exercised group (N=99, pH 6.14) was significantly higher in comparison to the muscles from non-exercised (N=100, pH 5.85, p=0.000). Exercise stress also resulted in differences in other meat quality measurements. Colour, cooking loss and shear force of some muscles were changed after exercise stress. REIMS analysis found clear metabolite-based differences between muscles from exercised and control sheep, and between muscles. Conclusion: We have developed a model for generating high pH lamb based on farmyard pre-slaughter stress. This resulted in changes to several important meat quality markers. Samples from this trial have been used for fingerprinting mass spectrometry to identify new potential predictive markers of high ultimate pH. This simple farmyard stress model is a useful tool for research on high pH meat under controlled yet realistic conditions, and follow up validation trials has confirmed the reproducibility of this model. In future, biomarkers of high pH in the meat could be used for enhancing animal welfare and confirm the relationship between minimising pre-slaughter stress and improving the consistency of meat quality.Item Open Access Nearly 50% of researchers quit science within a decade, huge study reveals (women in the science field too)(2024) Lee, HannahPresentation given at AKC 2024 - Women's Scientists Forum.Item Open Access Disease prediction for parasite: Gastrointestinal nematode infection as a model for the impact of chronic stress on meat qualityLee, Hannah; Ross, Alastair; Greer, Andrew; Slow, Sandy; Morton, JamesPresentation given at the AgResearch & Meat Industry Association Meat Innovation Workshop, 26 March 2024.Item Open Access Changes in total soluble solids concentration, fruit acidity, and yeast assimilable nitrogen in response to altered leaf area to fruit weight ratio in Pinot noir(The International Viticulture and Enology Society (IVES), 2024) Assefa, MK; Creasy, GL; Hofmann, RW; Parker, AmberThe increasing consumer demand for lower alcohol wine and the need to mitigate against a warming climate presents new challenges for winegrowers and the desire to produce grapes with lower total soluble solids (sugar) or earlier harvesting, while preserving other wine compounds and attributes, particularly for varieties intended for red wine production. We investigated how reducing vine leaf area through shoot trimming and leaf removal, applied at different severities and timings to modify the leaf area to fruit weight (LA) ratio, affects fruit composition for producing lower alcohol quality Pinot noir wine. Shoot trimming treatments (half canopy, H in 2015/16 and 2016/17, and quarter canopy, Q in 2016/17 by alternately removing leaves after trimming shoots to half) were applied shortly before veraison (V-, E-L 34), during veraison (V, E-L 35) and post-veraison (V+, E-L 36) in three different vineyard locations (Marlborough, Canterbury and Central Otago, New Zealand). Untrimmed vines served as the control. Lateral shoots were removed during treatment application, and regrowth was removed to maintain a consistent leaf area. Results showed that reducing the LA:FW ratio delayed the accumulation and concentration of total soluble solids (reduction of 1.0 to 2.7 °Brix) at harvest in all trimmed vines over both seasons. Berry weight, malic acid concentration, titratable acidity, and pH at harvest were unaffected by trimming. At target TSS levels of 18 °Brix (10 % ethanol, v/v) in the Marlborough vineyard and 20 °Brix (11 % v/v) in the Central Otago vineyard, V+ vines showed malic acid and titratable acidity levels comparable to the control. At the Canterbury vineyard, these parameters remained similar across all treatments at 16 °Brix (8.9 % v/v). Yeast-assimilable nitrogen concentration increased (188 to 411 mg/L) in early trimmed vines. At Central Otago, roots showed lower carbohydrate reserves across all trimming treatments, likely due to the high yield at the site, while at Canterbury, trimming did not result in significant differences in carbohydrate reserves, likely due to the low yield at the site. At the Marlborough vineyard, vines trimmed early and more severely had less starch in their roots, while HV+ vines maintained similar levels of starch to controls. In conclusion, halving the canopy post-veraison (HV+, LA 0.70 m²/kg as observed in Marlborough) could be considered a viable viticultural option to lower sugar accumulation, thereby reducing potential alcohol content, without affecting titratable acidity and pH. This practice offers significant potential for adapting to a warming climate and producing lower alcohol Pinot noir wines in a sustainable manner.Item Open Access Identification of the best viticultural areas by spatial optimisation. Application in New Zealand South Island in the context of climate change(The International Viticulture and Enology Society (IVES), 2024) Hamon, Baptiste; Thibault, Jeanne; Tissot, Cyril; Parker, Amber; Quénol, HervéThe global winegrowing sector is under pressure due to the effects of global climate change. This is particularly true for New Zealand, where the wine industry is limited to a few regions. This study focuses on the South Island of New Zealand. It uses the Multi-objective Optimisation for Agrosystems (MOA) model to (i) investigate how potential exposure to climate risks and phenological stages will evolve under climate change, (ii) assess the suitability of current vineyards for viticulture in the future, and (iii) investigate potential emerging areas favourable for viticulture. The results show that a significant shift in the phenological stages of veraison and ripeness can be expected in the future due to the warming of the South Island of New Zealand. The projected phenological stages advancement is around one week in the near term for both Shared-Socioeconomic Pathways studied (SSP2-4.5 and SSP5-8.5) and is more than three weeks and one month in long-term for SSP2–4.5 and SSP5-8.5 respectively. A regional to local increase in frost risk (Canterbury, Otago, and Southland) and a slight increase in disease risk (especially on the coast) are also projected in the future, while the South Island of New Zealand is not expected to be affected by heatwaves. The results show that Marlborough, New Zealand's most important winegrowing region, will continue to be one of the best areas for viticulture in the 21st century. On the other hand, new winegrowing opportunities are expected to emerge inland and southwards. Overall, this study contributes to the understanding of the impact of climate change on the New Zealand wine industry and emphasises the need to adapt to changing climate conditions. It also provides insights into the future suitability of vineyards and identifies potential expansion areas for the New Zealand viticulture sector.Item Open Access Effect of ultrasonic-pretreatment on soaking kinetics, nutritional, anti-nutritional, and functional properties of guar seeds(Elsevier Ltd., 2024-12-01) Kheto, Ankan; Chaudhari, Aditi; Manikpuri, Sakshi; Sehrawat, Rachna; Gul, Khalid; Kumar, Lokesh; Khan, Khursheed AlamThe study aimed to understand how varying the amplitude (25, 50, and 75%) and duration (15, and 30 min) of ultrasonic (US) pretreatment affected the soaking kinetics, nutritional, anti-nutritional factors (ANFs), in-vitro protein digestibility, and functional properties of guar seeds (GS). The GS required ∼1080 min to hydrate and absorbed ∼4.66 times higher moisture content. The US pretreatment reduced ∼55.55% of soaking duration compared to control. Soluble protein and fat content was significantly (p < 0.05) varied with US-treatment conditions. The water absorption capacity and foaming capacity of GSF samples gradually improved. Expect 75% amplitude, bioactive compounds in GSF begin to rise with longer duration and amplitude than control. Noticeable reduction of ANFs was observed in US-pretreated soaked GSF samples. As observed from FTIR and XRD analysis, US pretreatment might have reorganized structure orientation. Meanwhile, in-vitro protein digestibility gradually increased with US amplitude and duration. From multivariant analysis, 75% amplitude-15 min of US pretreatment may be a better option for shorter soaking time, and lesser ANFs. Therefore, US pretreatment could be helpful in increasing the protein extraction yield of GS. Furthermore, US-pretreated soaked GS might be useful to formulate bakery items.Item Open Access Effects of retained node numbers on berry maturity and yield components of cane-pruned Sauvignon blanc(The International Viticulture and Enology Society (IVES), 2024-07) Epee, PTM; Schelezki, Olaf; Trought, MCT; Werner, A; Hofmann, RW; Almond, Peter; Charters, Stuart; Parker, AmberCane pruning is used in most New Zealand Sauvignon blanc vineyards to manage yield, vine balance (relationship between vegetative growth and fruit growth) and fruit primary and secondary metabolites. The source–sink ratio (TLA/FM—total leaf area to fruit mass or ELA/FM—exposed leaf area to fruit mass), the fruit mass to pruning mass (FM/PM), the fruit mass to cane mass (FM/CM) and fruit composition provide an assessment of the vine performance and balance. The interpretation of these metrics (i.e., TLA/FM, ELA/FM, FM/PM, FM/CM) requires their comparison with known optimal ranges specific to cultivars, locations and growing conditions. More often, such context-and cultivar-specific optimal ranges do not exist, thus warranting research to investigate them. To understand the influence of retained node numbers on the vegetative and fruit development of Sauvignon blanc, grapevines were pruned across three vineyard sites (two in Marlborough—Site 1 and 2, and one in Waipara— Site 3) over two growing seasons, retaining 10, 20, 30, 40 and 50 nodes on one to four canes (each cane carrying ten nodes, with 50-node vines carrying on average 12.5 nodes on each of the four canes). The accumulation of soluble solids (TSS) generally increased at lower node numbers and vine yields, reflecting an increase in ELA/FM, with 50-node vines having the least TSS concentration at harvest. The average berry mass, titrable acidity (TA) and pH were unaffected by node numbers over the two seasons. A low source–sink ratio induced by high node numbers not only reduced the vine capacity to ripen the current crop but also reduced the following season’s bunch number per shoot (from 1.8 to 1.6 bunches per shoot; p < 0.05), average bunch mass (from 82.0 ± 6 g to 67.7 ± 3 g; p < 0.01) and bunch mass per shoot (from 153.5 ± 15 g to 106.7 ± 9 g; p < 0.05). When compared to 50-node vines, 10-node vines had a two-fold increase in the average cane mass (from 30.1 ± 3.9 g to 69.2 ± 8.7 g; p < 0.001) and average old cane mass (from 82.4 ± 6.9 g to 163.8 ± 21 g; p < 0.001). The ELA/FM and TLA/FM required for optimal TSS accumulation were 0.75 m² kg-1 and 2.0 m² kg-1, respectively, across all sites. A source–sink ratio above these values resulted in high average cane mass and average old cane mass (an indication of excess vigour), while lower values indicated reduced vigour and slowed TSS accumulation. This research provides useful optimal ranges to compare and interpret vine balance metrics measured at those sites.Item Open Access Probing biological nitrogen fixation in legumes using Raman spectroscopy(MDPI, 2024-08) Jafari, A; Seth, K; Werner, A; Shi, S; Hofmann, R; Hoyos-Villegas, VBiological nitrogen fixation (BNF) by symbiotic bacteria plays a vital role in sustainable agriculture. However, current quantification methods are often expensive and impractical. This study explores the potential of Raman spectroscopy, a non-invasive technique, for rapid assessment of BNF activity in soybeans. Raman spectra were obtained from soybean plants grown with and without rhizobia bacteria to identify spectral signatures associated with BNF. δN¹⁵ isotope ratio mass spectrometry (IRMS) was used to determine actual BNF percentages. Partial least squares regression (PLSR) was employed to develop a model for BNF quantification based on Raman spectra. The model explained 80% of the variation in BNF activity. To enhance the model’s specificity for BNF detection regardless of nitrogen availability, a subsequent elastic net (Enet) regularisation strategy was implemented. This approach provided insights into key wavenumbers and biochemicals associated with BNF in soybeans.Item Open Access Quality enhancement of Barramundi kamaboko using vortex fluidic device modified starch and fish gelatin(Frontiers Media SA, 2024-11-01) Lin, Jiayi; Wu, Yixiao; Wang, Hao; Jellicoe, Matt; He, Shan; Young, David J; Thennadil, Suresh; Raston, Colin L; Brennan, Charles; Tian, Bin; Abukhadra, Mostafa R; El-Sherbeeny, Ahmed MIntroduction: Prime quality kamaboko (cooked surimi) is produced from Alaska pollock. The main challenge of using cheaper fish fillets, including Barramundi, is achieving similar textures. Methods: Combined with fish gelatin, modified starch by vortex fluidic device was used to enhance the quality of kamaboko made from Barramundi. Results: Modification by a continuous flow vortex fluidic device (VFD) significantly reduces the size of particles of starch relative to conventional homogenization. Blending this VFD-modified starch with fish gelatin resulted in a well-organized cross-linked matrix compared to products manufactured from homogenization modified starch. This led to higher gel strength of the former (1,708.32 g/cm² ) relative to the latter (832.56 g/cm² ). Mixing different proportions of fish gelatin and VFD-processed starch to make Barramundi kamaboko (5, 10, and 15%), yielded a product with greater chewiness relative to Alaska pollock kamaboko. Sensory evaluation indicated that the 5% product was optimal and the 15% product with the highest chewiness (56.10 N) was the least favorable. Discussion: These results clearly indicate the potential of VFD processed starch, blended with fish gelatin to enhances the quality of kamaboko.Item Open Access Effect of succinylation on oxidation–aggregation of low-density lipoprotein and formation of off-flavors in heated egg yolks(Multidisciplinary Digital Publishing Institute (MDPI), 2024-11) Ren, Liuyang; Sun, Cheng; Lv, Ying; Kumar, LokeshThis study examined the effect of succinylation on protein oxidation–aggregation and the formation of off-flavors in heated egg yolks (EYs). The sensory evaluation, content of volatile compounds, stability of low-density lipoprotein (LDL) particles, and oxidation of lipid and protein at six levels of succinylated EY (0.25%, 0.5%, 1%, 2%, 5%, and 10%, w/w) were determined. The results showed that the succinylated thermal EY’s concentration of volatiles and off-flavors was reduced. Oil exudation and lipid and protein oxidation decreased with the improved succinylation degree. Succinylation also reduced the LDL particle size and changed the secondary structure (decreased the β-sheets and increased the α-helices) of protein in LDL particles. Meanwhile, succinylation could effectively change the thermal oxidation–aggregation of LDL protein by introducing succinyl groups with negative charges, thus increasing the stability of LDL particles in succinylated EY during heating. These results further revealed the relationship between the oxidation–aggregation of LDL and the formation of off-flavors in heated EY. These results also help improve the flavor quality of heat-treated EY and expands the application scope of egg products.Publication Embargo Effect of hemp protein hydrolysates on physicochemical properties and digestibility of starch : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science at Lincoln University(Lincoln University, 2024) Wu, GaoshengStarch is the main constituent of the human diet and is included in foods either in the gelatinized or retrograded form. This carbohydrate, produced by plants, contains amylose and amylopectin chains. Depending on the plant source, the proportion of these two glycan chains can vary within the granule, which influences the physicochemical behavior of starch in foods, impacting the textural and nutritional properties of the final food product. Over the past decades, researchers have investigated the impact of the presence and/or complexation of various biomolecules (proteins and polyphenols) with starch on its physical, chemical, and nutritional properties. There is limited research on the development of hemp protein and its hydrolysates in combination with various starch molecules, which could be a promising strategy for enhancing the nutritional and health benefits of foods. Exploring the interaction between hemp protein and different starches could lead to novel functional food ingredients with improved nutritional profiles, offering potential for increased health benefits. Firstly, this study compared the functional and nutritional properties of hemp protein hydrolysates (HPH) prepared with 0.5% Bacillus licheniformis (1 minute) and 2% pepsin protease (60 minutes). Hemp protein hydrolyzed by bacterial protease (HPHB) showed enhanced emulsifying capacity of 47.83 mL/g, compared to 45.83 mL/g for hemp protein hydrolyzed by pepsin (HPHP). On the other hand, HPHP exhibited superior oil absorption capacity of 5.46 g/g, compared to 5.18 g/g for HPHB, as well as higher foaming capacity at 31.2%, relative to 28% for HPHB. The amino acid composition, which affects the overall amino acid profile, was determined using High-Performance Liquid Chromatography (HPLC), a precise technique for separating and quantifying individual amino acids. Secondly, when the effects of HPH on the textural, particle size distribution, structural, and rheological properties of normal corn starch (NCS), waxy corn starch (WCS), and high amylose corn starch (HACS), alongside their impact on antioxidant activity and starch digestibility were examined, this study showed the addition of the HPH to the starch significantly modified the textural properties of starch gels, particularly enhancing elasticity and hardness in WCS and NCS and increasing adhesiveness in NCS and HACS. Notable effects were observed with 20% HPHP on WCS elasticity (0.09 N.s), 10% HPHB on WCS hardness (0.57 N), and 20% HPHB on WCS adhesiveness (-0.15 N) (p<0.05). Particle size distribution indicated substantial granule size increases, especially in HACS (e.g., Dx90 increased from 39.19 μm to 771 μm). FT-IR analysis revealed shifts in absorption peaks, suggesting altered hydrogen bonding interactions without new functional groups. Rheological properties varied, with increased storage (G') and loss (G") moduli in NCS-HPH mixtures and general decreases in WCS-HPH and HACS-HPH. Additionally, a significant reduction in rapidly digestible starch (RDS) was observed with 20% HPHP in HACS, while resistant starch (RS) increased by about 10% with 10% HPHB in WCS (p<0.05). Among the starches, 20% HPHP exhibited the highest antioxidant activity with 232.36 μmol TE/g for HACS, 231.60 μmol TE/g for WCS and 210.42 μmol TE/g for NCS, respectively (p<0.05).Item Open Access Bacterial cellulose infusion: A comprehensive investigation into textural, tribological and temporal sensory evaluation of ice creams(Elsevier B.V., 2024-11) Mehta, Annu; Kumar, Lokesh; Serventi, Luca; Morton, James; Torrico, DamirThe study examines how adding bacterial cellulose also referred to as Symbiotic Culture of Bacteria and Yeast (SCOBY) to ice cream affects the textural, tribological, and sensory attributes, particularly texture and mouthfeel perception. Analytical assessments were performed on three types: SCOBY-added ice cream and two reference samples (control and guar gum-added ice creams). Evaluations included physicochemical properties, textural and tribological characteristics, and dynamic sensory mouthfeel using the temporal dominance of sensation (TDS) methodology. SCOBY ice cream showed higher probiotics content, lower pH, and higher acidity than reference samples. The addition of SCOBY increased hardness and altered the textural properties. TDS analysis highlighted distinct temporal dominance patterns, with guar gum ice cream presenting a pronounced mouth/residual coating pre-swallowing, while SCOBY and control ice cream exhibited a thin/fluid perception. The frictional factor at 37 ⁰C was positively correlated with the melting rate, graininess, and thin/fluid perception while negatively correlated with firmness, smoothness and mouthfeel liking. Additionally, the mouthfeel liking was higher with firm, smooth and mouth/residual coating sensations and lower with grainy and thin/fluid perception. In summary, incorporating SCOBY in ice cream formulations can provide health benefits and meet consumer preferences for natural ingredients, while ensuring careful optimization of mouthfeel.Item Open Access Food contamination: Major challenges of the future(Multidisciplinary Digital Publishing Institute (MDPI), 2016-06) Hussain, MalikThis issue of Foods is dedicated to discuss the microbial, chemical and physical contamination challenges of food products. Food contamination is generally defined as foods that are spoiled or tainted because they either contain microorganisms, such as bacteria or parasites, or toxic substances that make them unfit for consumption. A food contaminant can be biological, chemical or physical in nature, with the former being more common. These contaminants have several routes throughout the supply chain (farm to fork) to enter and make a food product unfit for consumption. Bacillus cereus, Campylobacter jejuni, Clostridium botulinum, C. perfrigens, Pathogenic Escherichia coli, Listeria monocytogenes, Salmonella spp., Shigella spp., Pathogenic Staphylococcus aureus, Vibrio cholera, V. parahaemolyticus, V. vulnificus and Yersinia enterocolitica are common bacterial hazards (a type of biological contaminant). Chemical food contaminants that can enter the food supply chain include pesticides, heavy metals, and other alien chemical agents.Item Open Access Effects of apple juice concentrate, blackcurrant concentrate and pectin levels on selected qualities of apple-blackcurrant fruit leather(Multidisciplinary Digital Publishing Institute (MDPI), 2013-09) Diamante, Lemuel; Li, Siwei; Xu, Qianqian; Busch, JanetteA study was conducted to determine the effects of different levels of apple juice concentrate (AJC), blackcurrant concentrate (BCC) and pectin on the moisture content, water activity, color, texture and ascorbic acid content of apple-blackcurrant fruit leather using the response surface methodology. The results showed the moisture content increased with increasing pectin level and with greater increases at higher AJC and BCC levels while the water activity increased with increasing pectin level and with increasing AJC level, at low pectin levels, but with decreasing AJC, at high pectin levels. The chroma decreased with increasing pectin level and with lower values at the middle AJC level. The puncturing force decreased with increasing AJC level but with a lower value at the middle pectin level. Lastly, the ascorbic acid content increased with increasing BCC level regardless of AJC and pectin levels. There is a need to reduce the drying temperature or time of apple-blackcurrant fruit leather just enough to bring the water activity closer to 0.60, thereby increasing the moisture content resulting in higher product yield.