Dynamics of rapid starch gelatinization and total phenolic thermomechanical destruction moderated via rice bio-extrusion with alpha-amylase activation

Abstract

The simultaneous extrusion and enzymatic hydrolysis (bio-extrusion) processing of starchy food materials shows better bioaccessibility of various bioactive compounds, while its mechanism as well as the conditions controlling it are still undetermined for industrial application. The aim of this study was to investigate the influence of bio-extrusion on the kinetics of total phenolics as rapid starch gelatinization occurred.Glutinous rice was primarily extruded with/without thermostable a-amylase (0-1&) at different feed rates (F, 1.5-3.0 kg h À1 ), screw speeds (N, 100-200 rpm), moisture content (M, 22-38%) and barrel temperature (T, 80-100 C). High-efficiency enzymatic extrusion (with F and N as independent variables) was then conducted using response surface methodology when controlled T and M were consistently stable for enzymatic activity. F, N, M and T all affected the degradation rate constants of phenolics (k P ) and starch (k G ). The original positive relationship between k P and k G was inverted when amylase was introduced into the extrusion process. The activation energy (E) of total phenolic destruction increased from 37.49 to 70.30 kJ mol À1, mainly because of the great decrease in die pressure, special mechanical energy and shearing action caused by the enzymatic hydrolysis of starch.

Biomass pretreatment with reactive extrusion using enzymes: A review

“…Moreover, traditional pretreatments intensive conditions, with high physical and chemical constraints, lead to higher biomass deconstruc tion but also to some vulnerable substances loss (e.g., polyphenols, flavonoids and vitamins). Xu et al (2017Xu et al ( , 2015 observed better phe nolic compounds and soluble solid content of other compounds re covery with bioextrusion. The hypothesis was that the mild but efficient material deconstruction allowed to liberate more secondary substances without degrading it.…”

“…Several publications focus on the introduction of enzymes during the extrusion process, reinforced by the observation that the α amylase could keep its activity during and after the extrusion process (Linko et al, 1978). Different sources of starch have been tested such as corn (Zea mays L.) (Chouvel et al, 1983), barley (Hordeum vulgare) (Linko et al, 1983a), wheat (Triticum aestivum) (Hakulin et al, 1983;Reinikainen et al, 1986), sago (Metroxylon sagu) (Govindasamy et al, 1997a) and more recently broken rice (Oryza sativa) starch (Li et al, 2013;Xu et al, 2017Xu et al, , 2015. Due to the time needed for the complete saccharification, the bioextrusion has mainly been limited to the li quefaction part, but some researchers intended to initiate the sacchar ification step as well (Hakulin et al, 1983;van Zuilichem et al, 1990).…”

“…Summary of starch bioextrusion characteristics with enzymes, substrates characteristics and corresponding responses (Hakulin et al, 1983;Linko et al, 1983b;Reinikainen et al, 1986;van Zuilichem et al, 1990;Govindasamy et al, 1997a,b;Vasanthan et al, 2001;Baks et al, 2008;de Mesa-Stonestreet et al, 2012;Li et al, 2013;Xu et al, 2017).…”

A high amylase‐producing bacterial strain exhibiting the phosphorus‐dissolving ability, isolated from freshwater aquaculture pond

“…Then, 100 µl solution culturing bacteria overnight was added into each hole and cultured at 37°C for 24 hr. After spraying the iodine solution, the diameters of the hydrolysis circles were measured (Xu et al., 2017).…”

Mechanoenzymatic Transformations in the Absence of Bulk Water: A More Natural Way of Using Enzymes

“…The biomass was washed with diluteaqueousa cetic acid priortohydrolysis. [149] on wheat, [156] corn, [157] sago, [152,155] and rice [158,159] starch by bioextrusion.…”