1,368 research outputs found
The threat against man and the reaction of the Christian - An economic viewpoint*
I refer here to the study on trade boycotts that I undertook on behalf of the Institute for the Advancement of Calvinism and on which this paper is largely based. When I have to discuss the subject of threatened man as seen from an economic angle, this theme would have been somewhat negative, should one not look further than the threat alone. Therefore it is more positive to discuss the challenges of present-day man. This remains my viewpoint throughout: View the economic phenomena realistically and identify the threat therein, but do not allow the threats of today ever to become more than the challenges of tomorrow and never forget — not only are there threats, but so also are there many more opportunities which we ought to avail ourselves of through our abilities
Enhancing the enzymatic browning inhibition capacity of Moringa oleifera seed extract via the Maillard reaction
The antioxidant and anti-browning activity of heated plant extracts have been attributed to the formation of Maillard reaction products (MRPs) via the Maillard reaction (MR). The inhibitory effect of heated Moringa oleifera (MO) seed extract on banana polyphenol oxidase (PPO) was investigated. The Plain MO seed extracts and those with added glucose and glycine (1.5 mM each) were heated at 100°C for 15, 30, 60 and 120 min. The pH and brown colour development decreased and increased significantly (P <0.05) with increased reaction time, respectively, with heated moringa glucose-glycine HMGGL for 120 min exhibiting the highest pH reduction (2.58) and darkest extracts at an L* value of 8.11. This phenomenon is associated with progression of the MR. With reference to enzymatic browning, heated MO seed extracts exhibited stronger inhibitory effect against banana PPO activity in vivo and in vitro than the unheated counterpart. Evident to this are the higher inhibition percentages and lower ΔE values. Among model systems, the highest in vitro browning inhibition was exhibited mostly by longer heating times of 60 and 120 min. Model system HMGGL 120 min proved to be superior at 96% inhibition, which was comparable to known synthetic commercial antioxidants such as ascorbic acid (AA) at 99%, as well as ethylenediaminetetraacetic acid (EDTA) and citric acid (CA), both at 100% inhibition. In vivo enzymatic browning inhibition followed a similar trend, where the brown pigment (melanin) intensified as shown by an increase in ΔE as the storage time increased from 0.5 to 24 h. The model system UMGGL exhibited highest inhibition of brown melanin (p <0.05). Although it was the best amongst other model systems, it was surpassed by synthetic antioxidants AA, EDTA and CA, which were ranked amongst the top three in inhibiting brown pigment formation in vivo. To further illustrate the effect of MR augmented MO seed extracts on enzyme activity inhibition, UMGGL 60 and 120 at 5 and 24 h storage surpassed the inhibitory effect of AA. At the said storage times, AA lost its inhibitory potential against pigment formation. This was due to oxidation of AA to form dehydroascorbic acid, which lacks inhibitory potential. This study proved that heating MO plant extracts increases their enzymatic browning inhibition potential, furthermore, the inhibitory capacity was heightened when reacted via the MR
- …