Effect of 3D printing conditions and post-printing fermentation on pearl millet fortified idli.

BACKGROUND: Three-dimensional (3D) printing is an emerging technology with numerous applications in the development of novel foods to meet personalized and special dietary needs. Using 3D printing, foods with modified textures and consistency can be prepared conveniently. In this work, an indigenous rice-black gram batter was fortified with pearl millet flour and 3D printed in the in-house developed extrusion-based food printer, Controlled Additive-manufacturing Robotic Kit (CARK™). The impact of material supply composition was investigated along with optimization of different printing parameters and an in-depth analysis of post-printing fermentation kinetics was undertaken. The shape changes in the 3D printed constructs during fermentation were analyzed using a pixel-count-based image-processing technique that correlates with the change in surface area. RESULTS: The addition of millet flour resulted in accelerated fermentation. At 20% w/w level, better printability with higher precision and layer definition was obtained at 800 mm min-1 of printing speed, 360 rpm extrusion motor speed, and 1.22 mm nozzle diameter with an extrusion rate of 15.57 mm3  s-1 . The constructs of pearl millet flour (PMF) fortified idli batter have shown good structural stability and creep recovery. Fermentation-assisted shape change was found to be significantly influenced by infill levels. Both raw and steamed constructs with 40% infill showed around 37% lower hardness than 100% infill constructs due to a porous inner structure with reduced expansion in the surface area/volume during fermentation. CONCLUSION: The results of the study provide insights into the scope of printing fermented foods through the food-to-food fortification approach and textural modification of foods using 3D printing by varying the infill levels. © 2022 Society of Chemical Industry.

Microfluidic assessment of nutritional biomarkers: Concepts, approaches and advances.

Among various approaches to understand the health status of an individual, nutritional biomarkers can provide valuable information, particularly in terms of deficiencies, if any, and their severity. Commonly, the approach revolves around molecular sciences, and the information gained can support prognosis, diagnosis, remediation, and impact assessment of therapies. Microfluidic platforms can offer benefits of low sample and reagent requirements, low cost, high precision, and lower detection limits, with simplicity in handling and the provision for complete automation and integration with information and communication technologies (ICTs). While several advances are being made, this work details the underlying concepts, with emphasis on different point-of-care devices for the analysis of macro and micronutrient biomarkers. In addition, the scope of using different wearable microfluidic sensors for real-time and noninvasive determination of biomarkers is detailed. While several challenges remain, a strong focus is given on recent advances, presenting the state-of-the-art of this field. With more such biomarkers being discovered and commercialization-driven research, trends indicate the wide prospects of this advancing field in supporting clinicians, food technologists, nutritionists, and others.

Improvement of nutrient bioavailability in millets: Emphasis on the application of enzymes.

Millets are a traditional staple food of the dryland regions of the world and are rich in essential nutrients like protein, fatty acids, minerals, vitamins, and dietary fiber. Also, millets commonly synthesize a range of secondary metabolites to protect themselves against adverse conditions. These factors are collectively termed anti-nutritional factors and the existence of these factors in millets might reduce the accessibility of the nutrients in humans. Some of these factors include protease inhibitors, tannins, non-starch polysaccharides-glucans, phytates, and oxalates each of which might directly or indirectly affect the digestibility of nutrients. Methods like soaking, germination, autoclaving, debranning, and the addition of exogenous enzymes have been used to reduce the anti-nutritional factors and elevate the bioavailability of the nutrients. This review summarizes various methods that have been used to improve nutrient bioavailability, specifically emphasizing the use of enzymes to improve nutrient bioavailability from millets. © 2021 Society of Chemical Industry.

Disinfestation techniques for major cereals: A status report.

Management of stored product insects is a major concern and widely researched topic in the food and grain processing and storage industry. In the scenario of estimated utilization of produces exceeding the production, postharvest losses should be properly controlled to feed the growing population. The prevailing disinfestation techniques are forced to meet regulatory standards and market demands. The resistance developed by insects, environmental concerns, and occupational hazards lead to the vanishing of many chemicals used in insect and pest management programs. Some of the major disinfestation techniques such as the use of chemical fumigants, ozone, irradiation, dielectric heating, extreme temperature treatments, and bio rational approaches are discussed, particularly on the storage of cereal grains and its products, as they contribute to a significant proportion of food consumed worldwide. Newer techniques such as nonthermal plasma and metabolic stress disinfestation and decontamination for stored pest control are developed and evaluated in different parts of the world. The knowledge about the mode of action of these disinfestation techniques is important to avoid the cross-resistance and multiple resistance developed by insects with frequently used techniques. Various alternatives to conventional fumigants are discussed in this review as there is a growing demand for toxic-free, environment-friendly, and, at the same time, efficient techniques.

Multilayer packaging: Advances in preparation techniques and emerging food applications.

In recent years, with advantages of versatility, functionality, and convenience, multilayer food packaging has gained significant interest. As a single entity, multilayer packaging combines the benefits of each monolayer in terms of enhanced barrier properties, mechanical integrity, and functional properties. Of late, apart from conventional approaches such as coextrusion and lamination, concepts of nanotechnology have been used in the preparation of composite multilayer films with improved physical, chemical, and functional characteristics. Further, emerging techniques such as ultraviolet and cold plasma treatments have been used in manufacturing films with enhanced performance through surface modifications. This work provides an up-to-date review on advancements in the preparation of multilayer films for food packaging applications. This includes critical considerations in design, risk of interaction between the package and the food, mathematical modeling and simulation, potential for scale-up, and costs involved. The impact of in-package processing is also explained considering cases of nonthermal processing and advanced thermal processing. Importantly, challenges associated with degradability and recycling multilayer packages and associated implications on sustainability have been discussed.

Microencapsulation of Garcinia fruit extract by spray drying and its effect on bread quality.

BACKGROUND: (-)-Hydroxycitric acid (HCA) is the major acid present in the fruit rinds of certain species of Garcinia. HCA has been reported to have several health benefits. As HCA is highly hygroscopic in nature and thermally sensitive, it is difficult to incorporate in foodstuffs. Hence, Garcinia cowa fruit extract was microencapsulated using three different wall materials such as whey protein isolate (WPI), maltodextrin (MD) and a combination of whey protein isolate and maltodextrin (WPI + MD) by spray drying. Further, these microencapsulated powders were evaluated for their impact on bread quality and HCA retention. RESULTS: Maltodextrin (MD) encapsulates had higher free (86%) and net HCA (90%) recovery. Microencapsulates incorporated breads had enhanced qualitative characteristics and higher HCA content than water extract incorporated bread due to efficient encapsulation during bread baking. Comparatively, bread with MD encapsulates showed softer crumb texture, desirable sensory attributes with considerable volume and higher HCA content. CONCLUSION: The higher HCA contents of encapsulate incorporated breads were sufficient to claim for functionality of HCA in bread. Comparatively, MD had efficiently encapsulated Garcinia fruit extract during spray drying and bread baking. Spray drying proved to be an excellent encapsulation technique for incorporation into the food system.

Art of Cross-Linking In Situ Bulk Perovskites for Efficient and Stable Photovoltaics.

Perovskites are hybrid materials containing templating organic linkers and inorganic halides with efficiencies that have superseded the efficiency of silicon-based photovoltaic devices (PVs) in a very short period of 10 years. Nevertheless, low ambient stability due to traps and ion migration caused hysteresis to remain the bottlenecks on the way to achieving higher operational stability with bulk perovskite-based PVs. In this context, herein we highlight the prospects of in situ cross-linking of linkers within the perovskite lattice either mediated by thermal means or attained photochemically that can maneuver the ambient as well as operational stability for enhanced power conversion efficiency for PV applications or could improve the conductivity of this hybrid semiconductor. Additionally, some important studies of additive engineering via in situ cross-linking that can affect the structure of perovskite in addition to defect passivation to endow ambient environment stability are highlighted herein.

Modeling and Simulation of 3D Food Printing Systems-Scope, Advances, and Challenges.

Food 3D printing is a computer-aided additive manufacturing technology that can transform foods into intricate customized forms. In the past decade, this field has phenomenally advanced and one pressing need is the development of strategies to support process optimization. Among different approaches, a range of modeling methods have been explored to simulate 3D printing processes. This review details the concepts of various modeling techniques considered for simulating 3D printing processes and their application range. Most modeling studies majorly focus on predicting the mechanical behavior of the material supply, modifying the internal texture of printed constructs, and assessing the post-printing stability. The approach can also be used to simulate the dynamics of 3D printing processes, in turn, assisting the design of 3D printers based on material composition, properties, and printing conditions. While most existing works are associated with extrusion-based 3D printing, this article presents scope for expanding avenues with prominent research and commercial interest. The article concludes with challenges and research needs, emphasizing opportunities for computational and data-driven dynamic simulation approaches for multi-faceted applications.