The retention and bioavailability of phytochemicals in the manufacturing of baked snacks

There is a growing body of evidence supporting the role that phytochemicals play in reducing the risk of various chronic diseases. Although there has been a rise in health products marketed as being "supergrains," "superfood," or advertising their abundance in antioxidants, these food items are often limited to powdered blends, dried fruit, nuts, or seeds, rarely intercepting the market of baked snacks. This is in part due to the still limited understanding of the impact that different industrial processes have on phytochemicals in a complex food matrix and their corresponding bioavailability. This review brings together the current data on how various industrial dehydration processes influence the retention and bioaccessibility of phytochemicals in baked snacks. It considers the interplay of molecules in an intricate snack matrix, limitations of conventional technologies, and constraints with consumer acceptance preventing wider utilization of novel technologies. Furthermore, the review takes a holistic approach, encompassing each stage of production-discussing the potential for inclusion of by-products to promote a circular economy and the proposal for a shift in agriculture toward biofortification or tailored growing of crops for their nutritional and post-harvest attributes.

Isothiocyanates from Brassica Vegetables-Effects of Processing, Cooking, Mastication, and Digestion

The formation of health-beneficial isothiocyanates (ITCs) from glucosinolates depends on a wide variety of plant-intrinsic factors (e.g., concentration of glucosinolates, activity of myrosinase, and specifier proteins) and on a multitude of extrinsic postharvest factors such as the conditions used during industrial processing, domestic preparation, mastication, and digestion. All of these factors contribute to a large variability in the formation of ITCs (and other breakdown products), as well as their intake and absorption upon consumption of Brassica vegetables. This uncertainty in ITC intake and absorption is a barrier for the determination of an optimal Brassica vegetable consumption pattern. In this review, the intrinsic and extrinsic factors that affect the formation, intake, and absorption of ITCs are described according to the most recent findings. The focus of this review includes the hydrolysis reaction mechanisms, the elucidation of the primary factors that play a role in the hydrolysis reaction, the influence of processing and cooking conditions, the effect of chewing, and the roles of the gastric and upper intestinal phases, including the effect of the meal composition (e.g., the effect of other meal compounds present during digestion) on the potential formation of ITCs.

A mechanistic perspective on process-induced changes in glucosinolate content in Brassica vegetables: a review

Brassica vegetables are consumed mostly after processing, which is expected to give beneficial effects on the vegetable properties, such as improved palatability and bioavailability of nutrients, or shelf life extension. But processing also results to various changes in the content of health promoting phytochemicals like glucosinolates. This paper reviews the effects of processing on the glucosinolates content by using a mechanism approach underlying processing method employed. Cultural differences between Eastern and Western preparation practices and their possible effect on glucosinolate retention are highlighted. Boiling and blanching considerably reduce the glucosinolate content mainly due to mechanisms of cell lysis, diffusion, and leaching, and partly due to thermal and enzymatic degradation. Steaming, microwave processing, and stir frying either retain or slightly reduce the glucosinolates content due to low degrees of leaching; moreover, these methods seem to enhance extractability of glucosinolates from the plant tissue. Fermentation reduces the glucosinolate content considerably, but the underlying mechanisms are not yet studied in detail. Studying the changes of glucosinolates during processing by a mechanistic approach is shown to be valuable to understand the impact of processing and to optimize processing conditions for health benefits of these compounds.

Effect of water content and temperature on inactivation kinetics of myrosinase in broccoli (Brassica oleracea var. italica)

Broccoli belongs to the Brassicaceae plant family consisting of widely eaten vegetables containing high concentrations of glucosinolates. Enzymatic hydrolysis of glucosinolates by endogenous myrosinase (MYR) can form isothiocyanates with health-promoting activities. The effect of water content (WC) and temperature on MYR inactivation in broccoli was investigated. Broccoli was freeze dried obtaining batches with WC between 10% and 90% (aw from 0.10 to 0.96). These samples were incubated for various times at different temperatures (40-70°C) and MYR activity was measured. The initial MYR inactivation rates were estimated by the first-order reaction kinetic model. MYR inactivation rate constants were lower in the driest samples (10% WC) at all studied temperatures. Samples with 67% and 90% WC showed initial inactivation rate constants all in the same order of magnitude. Samples with 31% WC showed intermediate initial inactivation rate constants. These results are useful to optimise the conditions of drying processes to produce dried broccoli with optimal MYR retention for human health.