Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) - a novel coronavirus has rapid spread, and caused community infection around the globe. During the absence of a vaccine, people focused more on an immunity-boosting diet and needed clear knowledge about immunity-boosting foods. However, after the vaccination drive, the importance of food as a natural source of immunomodulation cannot be neglected. So, the purpose of this review was to describe the role of vital nutrient in boosting immune system of body apart from other factors like adequate sleep, exercise, and low stress levels. Macrophages, neutrophils, natural killer cells, dendritic cells, B-cells, and T-cells are the important components having important role in maintaining immunity of the human body. The first four-act as the initial mediators of innate host defense, and the latter two produce antibodies for pathogen destruction. The review investigated vital nutrients like vitamin-C, A, E and D, iron, zinc, folic acid, probiotics, and prebiotics affecting these immune components in some extent. Fruits, vegetables, spices, herbs, seeds, nuts, cereals, millets, and superfoods like chlorella and spirulina are good sources of these nutrients. However, fortified foods, functional foods, encapsulated foods with bioactive compounds and plant-based foods have shown immense potential in boosting immunity against viral infections like COVID-19. Some clinical trials and retrospective cohort studies have shown reduction in the severity of COVID-19 patients with relation to plant-based diet, vitamin D and C doses, probiotic, and zinc salts application.

The protein content of a plant-based ingredient is generally lower than its animal food counterpart, and research into novel alternative protein is required that can provide similar protein content, texture and appearance as meat. This work investigates a mycelium-based low moisture meat analogue (LMMA) approach, by incorporating 0 to 40% w/w mycelium (MY) into pea protein isolate (PPI) via extrusion using a twin-screw extruder at 140 °C die temperature, 40 rpm screw speed, and 10 rpm feeder speed (0.53–0.54 kg/h). Physicochemical, rehydration, and structural properties of LMMA were assessed. The MY incorporation led to a significant change in color attributes due to Maillard reaction during extrusion. Water solubility index and water absorption capacity increased significantly with MY addition, owing to its porous structure. Oil absorption capacity increased due to increased hydrophobic interactions post-extrusion. Protein solubility decreased initially (upto 20% w/w MY), and increased afterwards, while the water holding capacity (WHC) and volumetric expansion ratio (VER) of LMMA enhanced with MY addition upto 30% w/w. Conversely, WHC and VER decreased for 40% w/w which was verified with the microstructure and FTIR analysis. Overall, MY (30% w/w) in PPI produced a fibrous and porous LMMA, showing future potential with an increasingly plant-based product market and decreasing carbon footprint of food production activities.

Food-to-food fortification is an emerging technique to enrich the micronutrients in foods. Pertaining to this technique, noodles could also be fortified with natural fortificants. In this study, marjoram leaf powder (MLP) at a level of 2–10% was used as a natural fortificant to produce fortified rice noodles (FRNs) through an extrusion process. The MLP addition caused a significant increase in the iron, calcium, protein, and fiber in the FRNs. The noodles had a lower whiteness index than unfortified noodles but had a similar water absorption index. The water solubility index increased significantly due to the higher water retention ability of MLP. A rheological study showed a minimal effect of fortification on the gelling strength of the FRNs at lower levels. The microstructural studies found incremental cracks, which facilitated a lower cooking time and hardness but had an insignificant effect on the cooked noodle texture. Fortification improved the total phenolic content, antioxidant capacity, and total flavonoid content. However, no significant changes in bonds were observed, but a reduction in the noodles’ crystallinity could be seen. The sensory analysis of the noodles reflected a higher acceptability of the 2–4% MLP fortified samples compared to the others. Overall, the MLP addition improved the nutritional content, antioxidant activity, and the cooking time but slightly affected the rheological, textural, and color properties of the noodles.