FORMULATION OF ANTIOXIDANTS

Using the QSFR principle, delivery systems with physical stability could be designed. However, the long-term chemical stability of unsaturated (double bond containing) lipids (such as PUFAs, carotenoids, and CLA) is still a critical issue. The oxidation of dietary bioactive lipids results not only in the changes in sensory properties, but also may lead to the loss of its bioavailability [59]. There are various ways to combat such oxidation processes and one of the methods is the use of antioxidants [17]. The use of antioxidants in food industries is decreasing since most of the food industries are disinclined to use synthetic antioxidants due to their possible deleterious effects on human health and stem control over their level of incorporation. The aptness to control or prevent an oxidation of bioactive-lipid incorporated food products by synthetic antioxidants is often limited. In contrast, several natural antioxidants (rosemary extract, ascorbic acid, ascorbyl palmitate, and tocopherols) are currently being employed to protect the bioactive lipids from oxidation (stage 4 of Figure 1.3).

Therefore, there is an increasing demand to harness the existing antioxidants smartly within the food products. Regeneration of antioxidants could improve the effectiveness of antioxidants in finished products.

Regeneration of antioxidants is being affected by several factors and is often complicated in food products with multi-component matrices. The activity of an antioxidant molecule is strongly affected by its intrinsic properties (such as stoichiometry of electron transfer, molecular weight, polarity, and free radical scavenging ability). Besides, the partitioning and distribution of antioxidants, and physical location within food matrices or delivery systems also influence the antioxidant regeneration. As a result, the prediction of an antioxidant activity usually varies from the real food system. Free radical scavengers must be localized in such microenvironment, where there is a generation of lipid radicals, to maximize the efficiency. It is thus crucial to develop the simple techniques to easily locate the pairs of antioxidants during their regeneration.

DESIGNING FOODS WITH ADDED MICRONUTRIENTS

Micronutrients are required in minute quantities, but their absence results in severe consequences. Nowadays, the trend is increasing to incorporate micronutrients into various food products and beverages [76, 101, 112]. The food industry has been practicing addition of micronutrients into various food products since it is a cost-effective measure to alleviate micronutrient malnutrition. The biological effects, molecular characteristics, and physicochemical properties of micronutrients (vitamins and minerals) vaiy greatly. Iron, zinc, vitamins A and D, and vitamins-B are some of the most common micronutrients added to food products [10].

Due to a variety of physicochemical and biological limitations, some micronutrients cannot be truly integrated into the food products in their pure forms. The water and/or lipid solubility ought to be low, therefore, must be introduced in a unique form. These micronutrients may also be liable to degradation through preparation, processing, storage, or transport and thus are to be protected. Some of the micronutrients possess characteristics and distinguishable off-flavor. Their addition, therefore, can also limit the acceptability of the food products and flavor masking is, therefore, needed [72]. The bioactivity and thus stability of some micronutrients are adversely affected due to their interaction with some other food components. While the oral bioavailability of some micronutrients is inherently low or variable, and therefore their bioavailability must be enhanced by proper designing [53].

The molecular and the physicochemical characteristics and the nature of the food matrix influence the micronutrient degradation. The chemical instability of a micronutrient involves the change in its molecular form and may consequently result in drastic adjustments in the nutritional and physicochemical properties. The chemical degradation of micronutrients is catalyzed by way of enzymes or other activators existing within the food matrix and encompasses reduction, oxidation, isomerization, and hydrolysis [12]. The physical instability includes phase changes, separation, and aggregation. It is important to frilly understand the degradation mechanism for a specific micronutrient and to establish the fundamental elements (ionic strength, pH, temperature, oxygen, water activity, and light) accountable for such degradation. As a result, an effective delivery system for micronutrients could be designed to prevent or minimize the degradation [47, 68].

To have the beneficial effects, human body must absorb the active form of a micronutrient after ingestion. Therefore, the delivery systems are to be designed in such a way that it increases the micronutrient fraction that survives in the food. Nanoparticles are being used to encapsulate micro- nutrients possessing enhanced stability, functionality, and bioavailability [57]. Major advancements have taken place in the design of nanoparticles, which could be utilized to develop coherent and effective delivery system for micronutrients [74, 79, 101, 112].

Extrusion is also one of the technologies for micronutrient fortification and entails the injection of a solution of biopolyrner along with encapsulated BFC. Gelation could be carried by way of cross-lirrking agents, variations in temperature, and/or the extrusion of one of the biopolymers into an oppositely charged biopolymer solution [62, 72]. For example, calcium alginate beads could be formed by administering an alginate solution into a solution of calcium [66]. These biopolymer-based particles have shown excellent protection ability to vitamin D in addition to increasing its bioavailability [47]. Nanoencapsulated of vitamin D in casein is better preserved during long-term cold storage and their' level does not change even after thermal processing [47].

Before incorporating them into the food products, selection of a proper encapsulation process is a must. The stability of vitamins and thus their retention in food products depends on light, heat, oxygen, potential interactions, presence of transition metals and packaging [43]. These factors set the criteria for the design and development of microencapsulation systems to ensure the effective delivery of specific micronutrients. Apart from giving due consideration to the cost, scalability of technique, selection of an encapsulate material and regulatory compliance and safety, several other factors (such as stability, bioavailability), sensory characteristics of microencapsulated ingredients should be considered [43, 57].

 
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