No abstract

Cadmium (Cd) contamination is a highly dangerous international problem because it can transfer into the food chain and become bioaccumulated, endangering human health. Cd detoxication is very interesting particularly the method providing no undesirable side effects. Cd also causes lipid oxidation that leads to undesired food quality. Garlic (Allium sativum L.) has been used as conventional food and in herbal therapy and folklore medicine as an antibacterial, antitumorogenic, and antioxidant agent for over 5000 years. In the present work, fresh garlic and pickled garlic extracted with distilled water was brought to determine antioxidant activities in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging assay, ferric reducing ability power (FRAP) assay, chelating activities, superoxide, and hydroxyl scavenging assay. The data showed that pickled garlic extracts significantly possessed more DPPH, ABTS, FRAP, superoxide, and hydroxyl scavenging assays as 11.86, 13.74, 4.9, 46.67, and 15.33 g trolox equivalent/g sample, respectively, compared with fresh one as 7.44, 7.62, 0.01, 4.07, and 8.09 g trolox equivalent/g sample, respectively. However, iron chelating activity of fresh garlic extract was higher than that of pickled garlic while there was no significant difference in the copper chelating activity of both extracts. For anti-Cd properties, pickled garlic was more effective than fresh garlic and contained less toxicity than standard diallyl disulfide (DADS). Therefore, therapeutic properties of pickled garlic favored its consumption compared with fresh and standard DADS for its antioxidant and anti-Cd properties.

Glycation of the thermostable α‐amylase, KLE, from Bacillus subtilis occurred during incubation with maltodextrin at 95C. This was revealed by the release of 5‐hydroxymethyl‐2‐furfuraldehyde from the acid hydrolysis of glycated KLE (gKLE), the differences in the protein band patterns on SDS and Native‐PAGE, and the shifting of the pI value from the range of 5.6–6.5 to that of 5.2–6.5. After glycation, the activity of gKLE was still retained. Furthermore, gKLE was more resistant to heat and pH compared with the nonglycated enzyme. The Km, reaction rate and efficiency to convert gelatinized cornstarch into maltodextrin of KLE were remained unchanged after glycation. This was different from the result obtained for BAN, another thermostable α‐amylase produced by B. amyloliquefaciens. Glycation in BAN decreased the activity in converting gelatinized cornstarch into maltodextrin. Moreover, the stability and kinetic parameters of BAN were found to be negatively affected by glycation. PRACTICAL APPLICATIONS One of the major applications of starch is for the production of glucose, either in a form of crystalline or syrup which can be further processed into high‐fructose syrup. This is done by starch hydrolysis which is composed of two major enzymatic steps, i.e., liquefaction and saccharification. Liquefaction, converting gelatinized starch to maltodextrin, is carried out by the action of thermostable α‐amylase, while saccharification is by glucoamylase. During the process under the conditions of high concentration of reducing sugar and high temperature, thermostable α‐amylase can be glycated. This non‐enzymatic process occurs when reducing sugar and free amino groups are coexisted in the system. However, the glycated enzyme was found to be more stable than the native form. Hence, industrial thermostable α‐amylase with a suitable degree of glycation, can be more efficient in hydrolytic process.

The effect of lipids on antioxidant activities of tested antioxidants and Tom-Kha paste extract was determined in the food system. 2,2'-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) scavenging activity, peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and p-anisidine value (AV) were methods for determining. The result showed that heating at 121˚C for 15 min caused decreasing on DPPH scavenging activity of lauric acid but didn't affect ABTS scavenging activity of both lauric acid and virgin coconut oil. DPPH scavenging activity of all mixtures was significantly decreased (p < 0.05) after thermal processing. ABTS scavenging activity of the mixtures lauric acid and antioxidants was decreased at ratios 2:1 and 5:1 while at ratios as 10:1 and 15:1 were not changed after heating. Additionally, ABTS scavenging activity in systems of virgin coconut oil mixed with gallic acid and Trolox was decreased after heating. Surprising ABTS scavenging activity of p-hydroxycinnamic acid and Tom-Kha paste extract in both lauric acid and virgin coconut oil systems increased after thermal processing. In food systems of lauric acid, PV of almost mixtures except lauric acid-Tom-Kha paste extract 2:1 and lauric acid-Trolox 15:1 was increased after heating. TBARS value of the mixtures was not significantly different (p  0.05) after thermal processing. AV of only lauric acid-gallic was enhanced after heating. PV of virgin coconut oil added with all tested antioxidant was not changed after heating. TBARS of virgin coconut oil added with antioxidant samples seemed to slightly increase after heating. AV of virgin coconut oil with added gallic acid and Tom-Kha paste extract were not changed by heat treatment while AV of virgin coconut oil with added p-hydroxycinnamic acid and Trolox seemed to decrease after heating.