Production of Filamentous Fungal Biomass (Aspergillus awamori) in Pellet Form from Almond Hull Extract
Fungal cultivation using agricultural byproducts is a sustainable approach to produce valuable bioproducts for applications such as protein-rich foods. In this study, Aspergillus awamori (A. awamori) was cultivated in batch flasks to investigate the effects of different nitrogen sources and initial carbon to nitrogen (C/N) ratios of 15, 30, and 45 on fungal yield and characteristics using almond hull extract as a substrate. Yeast extract was identified as the most effective nitrogen source, while NH4Cl was selected to adjust the C/N ratio to reduce raw material costs. The highest fungal biomass concentration and yield were achieved at a C/N ratio of 15, at which the fungal biomass had the highest crude protein content of 18.10% and the lowest fat content of 2.28%. Environmental scanning electron microscope (ESEM) imaging revealed that fungal pellets transitioned from smooth and dense to hollow with uneven surfaces as cultivation progressed. Following the flask experiments, the effect of pH control and agitation on fungi growth was studied in 2 L bioreactor. The highest biomass yield (0.97 g TSS/g sugar), biomass concentration (15.01 g/L), and uniform pellet size (3.75 mm) were achieved at 150 rpm without pH control. This study demonstrated that almond hull extract can serve as a promising substrate for the production of fungal pellets.
https://doi.org/10.1007/s11947-025-03955-x
Efficacy of a continuous Dean flow UV-C system in almond milk treatment using computational fluid dynamics and biodosimetry
A continuous Dean flow UV-C system was designed using fluorinated ethylene propylene tubing with UV-C transmission ≈60% wrapped in a serpentine path to improve axial mixing with a Dean number > 140. The microbial inactivation efficiency of the system was evaluated using Salmonella Typhimurium, E. coli O157:H7, Staphylococcus aureus, Saccharomyces Cerevisiae, and T1UV inoculated in almond milk (AM) and treated at various fluence levels at an optimized flow rate of 515 mL/min. In addition, a detailed examination of the velocity magnitude at various locations in a dean flow system, especially at the bends, was quantified. The findings indicate that a reduction > 4 log10 CFU/mL was attained for all specified microorganisms with a reduction equivalent fluence of 22.05 mJ/cm2. Additionally, computational fluid dynamics were employed to examine the velocity magnitude and incident radiation field within the tubing. In summary, the system demonstrated effectiveness in inactivating target microorganisms present in almond milk. Incorporating UV treatment in the production line allows for more environmentally sustainable practices, reducing energy consumption, and may eliminate the need for additional preservatives in plant-based beverage manufacturing.
https://doi.org/10.1007/s11947-024-03626-3
Pulsed Light (PL) Treatments on Almond Kernels: Salmonella enteritidis Inactivation Kinetics and Infrared Thermography Insights.
Extending the shelf-life and ensuring microbiological safety of food products while preserving the nutritional properties are key aspects that must be addressed. Heat processing of food matrices has been the golden standard during the last decades, while certain non-thermal processing options have recently gained ground. In the present study, experimental pulsed light (PL) surface inactivation treatments of Salmonella enteritidis on almonds kernels are performed. The PL system is set to test different operative conditions, namely power (1000, 1250, and 1500 W) and frequency (1.8, 3.0, and 100.0 Hz) at different treatment times (from 5 to 250 s), which result in applied fluence doses in the 0-100 J·cm-2 range. Additionally, temperature measurements are collected at each operative condition on the almond surface (using infrared (IR) thermography) and at the superficial layer of the almond (1-mm depth using a thermocouple). The observed PL inactivation kinetics are then modelled using four different models. The best goodness-of-fit is found for the two-parameter Weibull model (R 2 > 0.98 and RMSE < 0.33 for all cases). The maximum achieved log-CFU reductions are 6.02 for the 1.8-Hz system, 4.69 for the 3.0-Hz system, and 3.66 for 100.0-Hz system. The offset between the collected temperature readings by the two sensors is contrasted against the inactivation rate (following the two-parameter Weibull model). It was found that the highest inactivation rate corresponds approximately to the point where the infrared camera detects a slowdown in the surface heating. https://doi.org/10.1007/s11947-021-02725-9