Consumer interest in meat and dairy alternatives drives demand for plant-based protein ingredients. While soy and gluten dominate the market, there is a trend to explore alternative crops for functional ingredient production. The multitude of ingredients poses challenges for food manufacturers in selecting the right protein. We investigated 61 commercially available protein ingredients from various sources, categorizing them based on their protein content into protein-rich flours (protein content less than 50%), protein concentrates (protein content between 50% and 80%), and protein isolates (protein content higher than 80%). Methionine, cysteine, and lysine were decisive for the amino acid score, which even varied between ingredients produced from the same raw material. Such differences were also observed in the protein solubility profiles, characterized by their raw material–specific protein pattern. By focusing on soy, pea, and fava bean ingredients, the broad spectra of emulsifying and foaming properties were illustrated. These ranged from non–emulsifying and non–foaming to high emulsifying capacities of 737 mL/g ingredient and foaming activities of 2,278%, accompanied by a foam stability of 100%. Additionally, we demonstrated that the functionality of ingredients obtained from different batches could vary by up to 24% relative SD. Protein solubility, powder wettability, color, and particle size were determined as key properties for the differentiation of soy, pea, and fava bean protein ingredients by principal component analysis. In our study conclusion, we propose essential measures for overcoming challenges in protein ingredient production and utilization to realize their full potential in fostering sustainable and innovative plant-based food production.

The objective of this work was to characterize banana peel polyphenol oxidase (PPO) and to study the inactivation kinetics during thermal and cold atmospheric pressure plasma treatment. Since varietal differences in enzyme characteristics are a well-known phenomenon, ‘Prata’ banana peel PPO was characterized, and PPO activity and thermal stability of the peel PPO of the two dessert banana cultivars ‘Cavendish’ and ‘Prata’ were compared to identify the cultivar better suited for industrial food applications. A crude extract obtained from the peels of the Brazilian banana variety ‘Prata’ revealed highest PPO activities (46.0–55.2 nkat/mL) at 30–40 °C in a range of pH 6.0–6.5 after addition of 0.5 g/g_sample polyvinylpyrrolidone and 0.5% (v/v) Triton X-100 during extraction. ‘Cavendish’ PPO activity was four times higher. Banana peel PPO exhibited the highest affinity towards dopamine (K_M = 0.94 mM). Thermal inactivation of ‘Prata’ and ‘Cavendish’ PPO was achieved at 90 °C after 5 and 15 min, respectively, whereas cold plasma treatment did not decrease PPO activity below 46% of the initial enzyme activity. The inactivation behavior of PPO could successfully be described by a two-fraction model indicating at least two types of isoenzymes with different thermal stability. The overall high thermal stability was mainly attributed to membrane-bound PPO. The results may help to prevent enzymatic browning of banana peels and thereby facilitate their valorization as food ingredients.

Wet coffee processing generates a large amount of coffee pulp waste that is mostly disposed of in the processing units. To reduce this waste and the associated environmental burden, an alternative strategy would be to exploit the coffee pulp to produce a durable and stable consumable product. Accordingly, a puree produced from Robusta coffee pulp was investigated in relation to its physicochemical and sensory properties. After thermal and chemical stabilization, the obtained puree (pH 3.6) was found to exhibit a multimodal particle size distribution, shear-thinning behavior, and lower discoloration, as well as an antioxidant capacity of 87.9 µmol_TE/g_DM. The flavor of the puree was examined by sensory evaluation and the corresponding analyses of aroma-active volatile compounds, as determined using aroma extract dilution analyses (AEDA) and gas chromatography-mass spectrometry/olfactometry (GC-MS/O). The puree was characterized by dominant fruity (4.4), floral (3.4), citrusy (3.3) and hay-like (3.3) odor impressions. The aroma-active compounds were predominantly aldehydes, acids, and lactones, whereby (E)-β-damascenone, geraniol, 4-methylphenol, 3-hydroxy-4,5-dimethylfuran-2(5H)-one, and 4-hydroxy-3-methoxybenzaldehyde exhibited the highest flavor dilution (FD) factor (1024), thereby indicating their high impact on the overall aroma of the puree. This study demonstrates an approach to stabilize coffee pulp to produce a sweet, fruity puree with comparable physical properties to other fruit purees and that can be used as a new and versatile flavoring ingredient for various food applications.