Vicky Ann Solah

This study investigated the effect of lecithin on the complexation of pea starch with aliphatic alcohols (C10–C18). Alcohols (C10–C16) produced cooling-stage viscosity peaks, while 1-octadecanol only showed increased final viscosity in ternary systems with lecithin during the Rapid viscosity analyzer program. Differential scanning calorimetry and complex index analyses revealed enhanced complex formation, with enthalpy changes nearly doubled compared to corresponding binary systems. X-ray diffraction showed increased V-type crystallinity (3.88–12.22 % to 8.36–21.10 %), while Fourier transform infrared and Raman spectroscopies confirmed improved short-range molecular order. Enzymatic hydrolysis demonstrated reduced digestibility, with 35.86 % resistant starch content in PS-10-LE after cooking. SEM and rheology studies indicated that lecithin addition caused network collapse and weaker gelation, likely due to more complex formation. These findings validated lecithin's role in enhancing starch-alcohol complexation and highlighted its potential for developing resistant starches with guests and encapsulating different flavor compounds, offering promising applications in food science.

A rapid and simple inductively coupled plasma atomic emission spectrometry (ICP OES) method was developed and validated for the determination of macroelements including calcium (Ca), phosphorus (P), potassium (K), sodium (Na), and magnesium (Mg) in Australian retail pasteurised milk. The milk samples were digested using the mixture of 70% HNO3 and 30% H2O2 (2 : 1, v/v) in an open-tube digester block at 120 degrees C for 4 h. The validated ICP OES method showed good linearity for all elements (R-2 > 0.9993). The method limits of quantification (LOQ) for Ca, P, K, Na, and Mg were 19.85, 8.97, 100.8, 41.92, and 11.56 mu gg(-1), respectively. Recoveries were in the range of 91.54-116.0%. Repeatability and interday reproducibility expressed as the relative standard deviation (% RSD) was below 5.0%. The contents of macroelements in 6 retail pasteurised milk samples were between 1099.32 and 1348.65 mu gg(-1) (Ca), 914.01 and 1091.21 mu gg(-1) (P), 1362.76 and 1549.74 mu gg(-1) (K), 288.89 and 323.22 mu gg(-1) (Na), and 97.62 and 110.57 mu gg(-1) (Mg). Principal component analysis (PCA) revealed that retail pasteurised milk samples were distinctly separated into four groups on the first two principal components (PCs). The difference in the macroelement content between milk brands might be affected by milk regions.

The fatty acid composition of Western Australian commercial pasteurised milk was profiled using gas chromatography-mass spectrometry (GC–MS). A total of 31 fatty acids (FA) were identified in the milk samples. The majority of FA were medium-chain fatty acids (MCFA) with 6–13 carbon atoms and long-chain fatty acids (LCFA) with 14–20 carbon atoms. The results of principal component analysis (PCA) showed significant differences in the levels of MCFA and LCFA in the different milk samples. The levels of MCFA and LCFA ranged from 10.09 % to 12.12% and 87.88% to 89.91% of total FA, respectively. C10:0 and C12:0 were the major components of MCFA comprising 3.46% and 4.22% of total FA, while C16:0 and C18:1 (cis 9-octadecenoic acid) represented the majority of LCFA with the levels of 26.18% and 23.34% of total FA, respectively. This study provides new insight into the FA composition of Western Australian pasteurised milk and differences in FA profiles which influence human health.

This paper investigates a newly found effect of lecithin on the complexation between starch and saturated fatty acids. Rapid visco analysis showed that adding lecithin to the pea starch-fatty acid mixtures resulted in a viscosity peak during the setback stage of the pasting curve. Subsequent differential scanning calorimetry showed that pea starch-fatty acid-lecithin systems formed more V-type structures than pea starch-fatty acid complexes. X-ray diffraction and Fourier transform infrared spectroscopy indicated the addition of lecithin developed the long-range and short-range order of the V-complexes. Small-angle X-ray scattering showed the ternary system had a more compact stack in nano-scale and smaller D bragg than the binary complex. In vitro enzymatic hydrolysis revealed higher hydrolysis resistance of ternary systems compared to binary complexes. The results of this research provide a mechanism for modifying starch-lipid complexes and contribute to scientific understanding of food ingredient interactions.

Highlights
• Lecithin facilitated complexation between starches rich in amylose and lauric acid.
• Lecithin did not enhance the complexation of amylopectin.
• The impact of lecithin was more pronounced in maize starch compared to potato starch.
• The formation of more complexes resulted in reduced enzymatic hydrolysis.

This research investigated the effect of lecithin on the complexation of lauric acid with maize starch, potato starch, waxy maize starch, and high amylose maize starch. Rapid visco analysis showed that lecithin altered the setback pattern of potato starch-lauric acid and maize starch-lauric acid mixtures but not waxy maize starch-lauric acid. Further investigation, including differential scanning calorimetry, complex index, and X-ray diffraction, showed that lecithin enhanced the complexation of maize starch, potato starch, and high amylose maize starch with lauric acid. Fourier transform infrared and Raman spectroscopy revealed increasingly ordered structures formed in maize starch-lauric acid-lecithin, potato starch-lauric acid-lecithin, and high amylose maize starch-lauric acid-lecithin systems compared to corresponding binary systems. These highly ordered complexes of maize starch, potato starch, and high amylose maize starch also demonstrated greater resistance to in vitro enzymatic hydrolysis. Waxy maize starch complexation however remained unaffected by lecithin. The results of this study show that lecithin impacts complexation between fatty acids and native starches containing amylose, with the starch source being critical. Lecithin minimally impacted the complexation of low amylose starch and fatty acids.

Enzymatic browning is a biological process that can have significant consequences for fresh produce, such as quality reduction in fruit and vegetables. It is primarily initiated by polyphenol oxidase (PPO) (EC 1.14.18.1 and EC 1.10.3.1) which catalyses the oxidation of phenolic compounds. It is thought that subsequent non-enzymatic reactions result in these compounds polymerising into dark pigments called melanins. Most work to date has investigated the kinetics of PPO with anti-browning techniques focussed on inhibition of the enzyme. However, there is substantially less knowledge on how the subsequent non-enzymatic reactions contribute to enzymatic browning. This review considers the current knowledge and recent advances in non-enzymatic reactions occurring after phenolic oxidation, in particular the role of non-PPO substrates. Enzymatic browning reaction models are compared, and a generalised redox cycling mechanism is proposed. The review identifies future areas for mechanistic research which may inform the development of new anti-browning processes.
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Consumers have shown increased interest in functional milk products that promote health and prevent disease.(Reference Nguyen, Busetti and Johnson1) Milk fat has an important nutritional role.(Reference Gómez-Cortés, Juarez and de la Fuente2) The purpose of this study (part of an Innovation Connections Grant with Bannister Downs Dairy) was to determine if quality or nutritional differences exist in milk processed in WA. Six different WA retail pasteurised whole milk products were provided by six dairy manufacturers and collected from two local supermarkets in March and September 2022. Milk composition was analysed using the Milkoscan FT1 (Foss, Hillerod, Denmark) for fat, protein, lactose and solids-non-fat (SNF) content. The separation and quantification of fatty acids (FAs) were performed using gas chromatography-mass spectrometry (GC-MS) (Agilent 7890 GC system fitted with a mass spectrometer detector (MSD) and a capillary column (30 m × 250 μm × 0.25 μm, DB-5 ms, Agilent). Whole milk colour measurements were measured using a BYK spectroguide handheld spectrophotometer to measure CIE L*, a*, b*. A discrimination test (Triangle test) was used to determine whether sensory differences existed between the different milk samples. Milkoscan protein, lactose and solids-non-fat (SNF) results were not significantly different between dairy manufacturers (p > 0.05) and one dairy manufacture's fat content (3.5%) was significantly higher than the others (p < 0.05). All dairy manufactures results matched their product nutritional panel. Fat content was 3.1–3.5%, protein content was 3.2–3.4%, lactose content was 4.6–4.8% and SFN content was 8.7–9.1%. Principal component analysis (PCA) showed significant difference in concentration of medium-chain fatty acids (MCFA) and long-chain fatty acids (LCFA) between WA milk samples. The level of MCFA ranged from 10.1% to 12.1% of the total identified fatty acids (FAs) determined and were predominantly C12:0 and C10:0. The level of LCFA ranged from 87.9% to 89.9% of total identified FAs. The C16:0 and C18:1 (8-octadecenoic acid) represented the majority of LCFA. PCA showed three significantly different groups. Colour was significantly different (p < 0.05). L* whiteness/brightness range was 43.2 to 70.6, a* greenness/redness range was −5.6 to +2 respectively, b* yellowness range was +1.6 to +5.9. Preliminary sensory evaluation results showed consumers (n = 23) could identify differences in milk colour and flavour (p < 0.05). Fatty acid profiles and sensory characteristics were significantly different between whole milk samples produced from different WA processors. The present study provides valuable information of FA composition in commercial milk for potentially developing alternative dietary fat sources and contributing to human health.

This study assessed the impact of heat treatment on beta-casomorphin 5 (β-CM5) and beta-casomorphin 7 (β-CM7) after in-vitro gastrointestinal digestion of milk representing beta-casein (β-CN) A1A1, A2A2 and A2I phenotype. After heat treatment at 73 °C/20 s, 85 °C/5 min and 121 °C/12 min, milk samples were subjected to in-vitro gastrointestinal digestion. β-CM5/7 were analysed using ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and further confirmed using ultra high-performance liquid chromatography-high resolution accurate mass Orbitrap™ mass spectrometry (UHPL-HRMS). β-CM5 was not released after in-vitro gastrointestinal digestion of all heated milk. Similarly, β-CM7 was not released in all milk with β-CN A2A2 phenotype. However, this peptide level ranged from 127.25 to 198.10 ng/mL (4.94–7.70 ng/mg protein) in heated milk with β-CN A1A1 phenotype, whereas it was released at much lower levels ranging from 19.35 to 24.50 ng/mL (0.71–0.91 ng/mg protein) in heated milk with β-CN A2I phenotype.

Nature has developed starch granules varying in size from less than 1 μm to more than 100 μm. The granule size is an important factor affecting the functional properties and the applicability of starch for food and non-food applications. Within the same botanical species, the range of starch granule size can be up to sevenfold. This review critically evaluated the biological and environmental factors affecting the size of starch granules, the methods for the separation of starch granules and the measurement of size distribution. Further, the structure at different length scales and properties of starch-based on the granule size is elucidated by specifying the typical applications of granules with varying sizes. An amylopectin cluster model showing the arrangement of amylopectin from inside toward the granule surface is proposed with the hypothesis that the steric hindrance for the growth of lamellar structure may limit the size of starch granules.

Previous research has not considered the effect of high amylose wheat noodles on postprandial glycaemia. The aim of the study is to investigate the effect of consumption of high amylose noodles on postprandial glycaemia over 2-h periods by monitoring changes in blood glucose concentration and calculating the total area under the blood glucose concentration curve. Twelve healthy young adults were recruited to a repeated measure randomised, single-blinded crossover trial to compare the effect of consuming noodles (180 g) containing 15%, 20% and 45% amylose on postprandial glycaemia. Fasting blood glucose concentrations were taken via finger-prick blood samples. Postprandial blood glucose concentrations were taken at 15, 30, 45, 60, 90 and 120 min. Subjects consuming high amylose noodles made with flour containing 45% amylose had significantly lower blood glucose concentration at 15, 30 and 45 min (5.5 ± 0.11, 6.1 ± 0.11 and 5.6 ± 0.11 mmol/L; p = 0.01) compared to subjects consuming low amylose noodles with 15% amylose (5.8 ± 0.12, 6.6 ± 0.12 and 5.9 ± 0.12 mmol/L). The total area under the blood glucose concentration curve after consumption of high amylose noodles with 45% amylose was 640.4 ± 9.49 mmol/L/min, 3.4% lower than consumption of low amylose noodles with 15% amylose (662.9 ± 9.49 mmol/L/min), p = 0.021. Noodles made from high amylose wheat flour attenuate postprandial glycaemia in healthy young adults, as characterised by the significantly lower blood glucose concentration and a 3.4% reduction in glycaemic response.