ABSTRACT
The pineapple (Ananas comosus) is an important tropical fruit in the world market. Its pulp has significant nutritional value while the peel and the core, in spite of being high in dietary fibre and nutrients, are generally considered to be agro-industrial waste. The aim of this research was to evaluate the effect that the integrated enzymatic and shear homogenization processes have on the physicochemical stability of pineapple base suspensions (pulp, core, and peel extract). Initially, an enzymatic hydrolysis process was evaluated with a completely randomized factorial design. Independent variables: incubation time (tinc) (1-4 h) and [enzyme] (0-200 ppm). Dependent variables: viscosity (µ) and particle sizes (D[3;2] and D[4;3]). The results showed a reduction of (µ) (70.7%), D[3;2] (54.2%), and D[4;3] (61.8%) for the optimized treatment (tinc = 3.2 h and [enzyme] = 200 ppm) compared to the control (t = 0, without enzyme). The effect of the integrated enzymatic treatment with a serial homogenization process was subsequently evaluated. Independent variables: high-speed homogenization time (t1) (15-20 min), recirculation time in high pressure homogenizer (t2) (3-7 min), and arabic gum (AG) (0.6-1.0%). Dependent variables: total suspension solids (TSS), zeta potential (ζ), µ, spectral stability index (R), D[3;2], and D[4;3]. The application of the integrated processes of enzymatic treatment and serial homogenization was more effective to be able to obtain a stable pineapple-based suspension. The experimental optimization of multiple responses defined t1 = 16.4 min, t2 = 7 min, AG = 0.98%, and TSs = 15.7 ± 0.5%, ζ = - 23.1 ± 0.4 mV, µ = 221 ± 11 cP, D[3;2] = 56.8 ± 2 µm and D[4;3] = 120.6 ± 4 µm and R = 0.58 ± 0.02 were obtained.
ABSTRACT
There is an urgent need for the ability to rapidly develop effective countermeasures for emerging biological threats, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the ongoing coronavirus disease 2019 (COVID-19) pandemic. We have developed a generalized computational design strategy to rapidly engineer de novo proteins that precisely recapitulate the protein surface targeted by biological agents, like viruses, to gain entry into cells. The designed proteins act as decoys that block cellular entry and aim to be resilient to viral mutational escape. Using our novel platform, in less than ten weeks, we engineered, validated, and optimized de novo protein decoys of human angiotensin-converting enzyme 2 (hACE2), the membrane-associated protein that SARS-CoV-2 exploits to infect cells. Our optimized designs are hyperstable de novo proteins ([~]18-37 kDa), have high affinity for the SARS-CoV-2 receptor binding domain (RBD) and can potently inhibit the virus infection and replication in vitro. Future refinements to our strategy can enable the rapid development of other therapeutic de novo protein decoys, not limited to neutralizing viruses, but to combat any agent that explicitly interacts with cell surface proteins to cause disease.
