R-phycoerythrin (RPE) from Palmaria palmata is a natural pink-red protein pigment with promising potential as a natural colorant. While being considered a more sustainable ingredient, its industrial implementation remains limited by costly, processing-intensive purification and stability challenges. This study develops and validates an integrated downstream process combining enzyme-assisted extraction, ultrafiltration-diafiltration, and spray drying to produce an RPE powder suitable for potential food applications. Among the tested enzymes, Shearzyme® Plus at 35 °C and 0.5% (w/w) enzyme dosage gave one of the best extraction performances, reaching 0.45 mg/mL RPE with a purity index of 0.73. Using a 100 kDa polyethersulfone membrane, RPE was concentrated with ultrafiltration-diafiltration to 1 mg/mL and an increased purity of 1.60, while recovering 90% of RPE and removing 91% of low-molecular-weight compounds. For the first time, spray drying of RPE was systematically optimized using response surface methodology. The optimized process also revealed a yield-solubility trade-off, highlighting the need to tailor drying conditions for the intended food application. Validation of the models confirmed that the predictions matched the experimental results within the confidence intervals, resulting in a 90.1 ± 0.6% powder recovery with a T g of 107.5 ± 0.4 °C and residual moisture content of 2.9 ± 0.5%, which is favorable for extended storage under ambient conditions. Spray-dried powders retained a reddish-pink color, although properties varied with processing conditions and addition of carrier, demonstrating the need to tailor powder color through spray-drying optimization. Overall, this work demonstrates a scalable and industrially relevant strategy for the production of RPE powders, and positions RPE as a potential novel food colorant.
This study aimed to understand the effects of different operational parameters and define the best conditions for applying high hydrostatic pressure to Tenebrio molitor paste, aiming to maximise benefits while minimising undesired effects on the quality of the final product. Three pressure levels (200, 400, 600 MPa) were applied to fresh mealworm paste for dwell times of 0- (control), 5-, 15-, 30-, 45- and 60-min. Microbial investigation of the studied pastes revealed a significant reduction in total viable count at pressures of 600 and 400 MPa, whereas no microbial reduction was observed at 200 MPa. A slight increase in titratable acidity was observed at every pressure, with the highest acidity measured for paste treated at 400 MPa for 60 min. Complete absence of lipid oxidation was measured at every pressure, with the peroxide value showing no significant differences. Similar behaviour was also observed for TBARs at 600 MPa. An increase in TBARs from short to long dwell time was observed at 400 and 200 MPa. The total phenolic content and antioxidant activity increased notably after the HHP treatment, with the highest values recorded at 400 MPa, regardless of the treatment time. A reduction in lipase activity was also observed at every pressure level, with a clear linear effect over treatment time. The process optimisation study revealed that 510 MPa applied for 31 min is the best treatment for maximising positive effects while minimising adverse effects. However, further studies should be conducted to validate and confirm the transferability of this observation.
Recommendations for sustainable diets agree on the need to reduce consumption of animal products, especially in wealthy countries. Legumes are expected to play a pivotal role in providing food protein substitutes in this context, but their adoption by consumers remains too slow to meet the sustainable development goals. Plant-based substitutes, such as yoghurt-like products, suffer from poorer sensory and nutritional properties than their dairy references. Milk-lupin blends with 67/33 or 50/50 w/w animal:plant protein ratios and fermentation with a Lactococcus lactis and Lactiplantibacillus plantarum co-culture were therefore proposed as a means to alleviate those issues. While milk-lupin blends significantly decreased the environmental burden of yoghurts, the protein digestibility of the milk-lupin blends exceeded 94% as assessed by in vitro digestion using the INFOGEST human adult protocol and analytical quantification of the total and bioaccessible individual amino acids. It even exceeded 97% after fermentation, which contributed more-than-additively to the release of peptides upon digestion. The calculated digestible indispensable amino acid scores (DIAAS) exceeded 100 in the fermented or non-fermented products regardless of the milk:lupin protein ratio. Meanwhile, the desirable supply of bioaccessible calcium and the undesirable environmental burden both increased with the animal:plant protein ratio, thereby evidencing that milk:legume blends are good compromises to address the counter-acting issues of dairy products and their plant-based substitutes.
This study aimed to understand the effects of different operational parameters and define the best conditions for applying high hydrostatic pressure to Tenebrio molitor paste, aiming to maximise benefits while minimising undesired effects on the quality of the final product. Three pressure levels (200, 400, 600 MPa) were applied to fresh mealworm paste for dwell times of 0- (control), 5-, 15-, 30-, 45- and 60-min. Microbial investigation of the studied pastes revealed a significant reduction in total viable count at pressures of 600 and 400 MPa, whereas no microbial reduction was observed at 200 MPa. A slight increase in titratable acidity was observed at every pressure, with the highest acidity measured for paste treated at 400 MPa for 60 min. Complete absence of lipid oxidation was measured at every pressure, with the peroxide value showing no significant differences. Similar behaviour was also observed for TBARs at 600 MPa. An increase in TBARs from short to long dwell time was observed at 400 and 200 MPa. The total phenolic content and antioxidant activity increased notably after the HHP treatment, with the highest values recorded at 400 MPa, regardless of the treatment time. A reduction in lipase activity was also observed at every pressure level, with a clear linear effect over treatment time. The process optimisation study revealed that 510 MPa applied for 31 min is the best treatment for maximising positive effects while minimising adverse effects. However, further studies should be conducted to validate and confirm the transferability of this observation.
