Significant innovations have occurred over the past 50 years in the malting and brewing industries, focused on optimization of the beer mashing, boiling and fermentation processes. One of the challenges faced in beer brewing has been in the malting process to obtain the desired malt and wort quality to produce high-quality beer products. The hydrolytic enzymes produced during grain germination are mostly entrapped inside the cellular matrices of the grain. The intra-grain diffusion of enzymes for in-situ hydrolysis, as well as diffusion of enzymes to wort, depends upon the malt size and malt size fractions obtained after milling. This review investigates the relationship between varying barley grain particle size distribution and the efficiency of the malting and mashing processes. Recommended ideal particle size of barley grain before and after milling are proposed based on the review of existing literature. Each brewing batch of grains with a proportion of >80% plump grains (>2.5 mm in size) is suggested to be the optimal size before milling, whereas the optimum grain particle size after milling ranged between 0.25 and 0.5 mm. The current review will summarize the theoretical aspects for malt milling and the particle size characteristics for optimizing the brewing process.

The bacterial production of polyhydroxyalkanoates (PHAs), a class of non-toxic, biodegradable, and bio-based polymers, has gained increasing attention as a sustainable alternative to petrochemical plastics. Among PHA producers, Cupriavidus necator H16 and Pseudomonas putida KT2440 are used for their ability to synthesise short- and medium-chain-length PHAs, respectively. While PHAs have been produced from simple hexoses like glucose and fructose, there remains a lack of systematic and integrated analysis linking carbon source, strain selection, monomer composition, and polymer crystallinity to blend behavior in ultrathin films. PHB and mcl-PHA production using Cupriavidus necator H16 and Pseudomonas putida KT2440 on glucose and fructose were compared herein. C. necator accumulated PHB up to 60 wt% on fructose and 45 wt% on glucose, with high molecular weight (0.7–1.3 MDa), while P. putida produced mcl-PHA up to 22 wt% on fructose and 18 wt% on glucose, with lower molecular weight (46–47 kDa) and a C6 – C12 monomer profile. Notably, C. necator exhibited extreme cell elongation (up to 30 μm) during PHB accumulation on fructose. Extracted polymers were systematically solvent-blended at defined ratios (100:0, 80:20, 60:40, 40:60, and 20:80 PHB:mcl-PHA) and cast into ultrathin films (~ 20 μm) with varying composition. Crystallinity was modelled using a Gaussian fitting approach on FTIR spectra via custom MATLAB code, enabling localised phase analysis and offering a rapid alternative to DSC for thin film crystallinity estimation. While film blends exhibited tunable crystallinity and multiple melting transitions, elongation at break was consistent across compositions, with increases observed at higher mcl-PHA content. This study provides a systematic comparison of PHAs from C. necator H16 and P. putida KT2440 grown on common hexoses, with full characterisation of monomer composition, molecular weight, and thermal behaviour to guide thin film bioplastic design. Blending PHB and mcl-PHA in ultrathin films revealed reduced melting points and crystallinity, likely due to reduced crystal size from film thickness constraints. This work offers a comparative reference for microbial PHA production and presents a strategy to design bioplastics with tunable properties for temperature-responsive packaging and drug delivery applications.

Microplastics are an environmental and dietary contaminant of significant concern for human health due to chronic exposure and emerging evidence of cellular impact. However, understanding of this impact is limited by challenges in their detection and identification in biological samples. This study aimed to use Optical Photothermal Infrared Spectroscopy (O-PTIR) to detect and characterize real-world microplastics internalized by intestinal cells, and to investigate the cellular impact of such exposure. An intestinal epithelial cell line (IEC-6) was exposed to physically degraded fluorescent microplastics (25-100 μg/mL) made of four polymers for 24 h. O-PTIR reference spectra were acquired on single dyed primary plastics before fluorescent guided O-PTIR was used to identify and characterize microplastics in IEC-6 cells. We determined that the limit of resolution under these conditions was particles of ∼ 1 μm. Microplastics from all polymer types were successfully detected and discriminated using O-PTIR data alone. Importantly, principal component analysis of cytoplasmic O-PTIR spectra was used to identify microplastic-induced metabolic shifts. This chemometric analysis suggested that microplastic exposure resulted in oxidative stress and metabolic disruption, indicated by conformational protein changes-including early signs of misfolding and aggregation-which are hallmarks of a stress-adaptive cellular response. Our findings demonstrate that O-PTIR is an efficient, non-destructive technique for label-free microplastic studies in biological samples, enabling the identification, localization and characterization of heterogeneous microplastics, while simultaneously revealing their impact on cellular function and composition.