Matching equilibrium water activity ($a_w$) to dried foods:

• $a_w = 0.87 - 0.80$: Pulses of high equilibrium moisture ($15-17\%$) -> (III)
• $a_w = 0.75 - 0.65$: Intermediate-moisture cereal flours/grains like rolled oats of $10\%$ moisture -> (I)
• $a_w = 0.60 - 0.50$: Dried extruded durum pasta of $12\%$ moisture content -> (IV)
• $a_w = 0.30 - 0.20$: Highly desiccated spray-dried whole milk powder of very low moisture ($2-3\%$) -> (II)

In food engineering and agricultural process engineering, the true volume and density of porous hygroscopic grains and powders are measured using the Toluene displacement pycnometric method. Unlike water (which causes hygroscopic swelling and dissolution of starches/sugars), toluene is a non-polar organic solvent that does not dissolve or hydrate the material, penetrates superficial micro-voids, and possesses low surface tension and low volatility.

Industrial enzyme producing microorganisms:

• Glucose isomerase: Produced commercially from actinomycetes like Streptomyces flavogriseus / S. murinus -> (III)
• Fungal Proteases: Sourced predominantly from Aspergillus oryzae -> (IV)
• Beta amylase: High-yielding microbial producer is Bacillus polymyxa (now Paenibacillus polymyxa) -> (I)
• Cellulase: Hyper-producing filamentous fungus is Trichoderma viride (T. reesei) -> (II)