Luận án: Snack Ngô Xơ Cao, Ép Đùn, Chiên, Chất Lượng Sản Phẩm - Yang Jin Han

VIETNAM NATIONAL UNIVERSITY - HO CHI MINH CITY HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY YANG JIN HAN CORN SNACK WITH HIGH FIBER CONTENT: EFFECTS OF MATERIALS, EXTRUSION AND FRYING PARAMETERS ON THE PRODUCT QUALITY DISSERTATION FOR THE DEGREE OF DOCTOR OF PHYLOSOPHY IN FOOD TECHNOLOGY HO CHI MINH CITY, 2021 VIETNAM NATIONAL UNIVERSITY - HO CHI MINH CITY HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY CORN SNACK WITH HIGH FIBER CONTENT: EFFECTS OF MATERIALS, EXTRUSION AND FRYING PARAMETERS ON THE PRODUCT QUALITY Major: Food Technology Major code: 62 54 01 01 Independent reviewer 1: Assoc. Phan Tҥi Huân Independent reviewer 2: Assoc., Medical doctor NguyӉn VăQ1Lên Reviewer 1: Assoc. Trӏnh Khánh SѫQ Reviewer 2: Assoc. Lý NguyӉn Bình Reviewer 3: Assoc.

Ngô Ĉҥi NghiӋp Scientific supervisor: Prof. Le Van Viet Man HO CHI MINH CITY, 2021 STATEMENT OF ORIGINALITY The author pledges that this is the work of the author himself. The research results and conclusions in this thesis are honest and not copied from any one source and in any form. The reference to the sources of documents has been cited and the reference sources are recorded as prescribed.

The author of the thesis Signature i ABSTRACT The objective of this study was to clarify the effects of commercial fiber preparations as well as the extrusion conditions on the quality of the fried corn snack. In addition, the study also focused on the effects of commercial natural antioxidants as well as the antioxidant content on the quality of palm olein oil during the frying of snack food. Finally, the obtained high fiber snack was in-vivo tested with the hyperlipidemia mice model to clarify its healthy benefits. The study consists of three sections.

Section 1 ± The use of commercial fiber preparation in the snack extrusion for improvement in the fiber content: Addition of fiber preparations such as polydextrose, xanthan gum, gum acacia, inulin, resistant starch and resistant maltodextrin to the extrusion blend changed physical and sensory properties of the obtained snack but the color of the product remained almost constant. Among the tested dietary fiber preparations, the polydextrose added snack had comparable physical and sensory quality to the control. When the polydextrose content in the blend varied from 0 to 10%, the bulk density of the fried extrudate increased while the radial expansion ratio and the crispiness decreased. The product with high polydextrose content had small air cells and thick cell walls.

For the extrusion conditions, the specific mechanical energy had a significant correlation with the water absorption index, water solubility index and bulk density in the screw speed section while in the die temperature section, there was correlation between instrument texture and sensory properties. The appropriate ratio of polydextrose in the mixing blend, extrusion die temperature and screw speed were 7,5%, 100 oC and 180 rpm, respectively. Section 2 ± The use of commercial natural antioxidants in the frying of the extruded corn snack: Commercial natural antioxidant preparations including citronella, nutmeg, clove and rosemary oil effectively prevented lipid oxidation of palm olein oil during the heating and extrudate frying process. Among the tested antioxidants, nutmeg and rosemary oils were more effective than tocopherol and BHT and the sample with nutmeg oil showed the highest oxidation stability.

For the extrudate frying, the nutmeg oil concentration of 4,0 g/kg was able to prevent oil degradation. ii Section 3 - Hypolipidemic and hepatoprotective effects of high polydextrose extruded corn snack on Swiss albino mice: The use of high polydextrose snack in the high fat diet reduced the triglyceride, total cholesterol and low density lipoprotein cholesterol content but increased the high density lipoprotein cholesterol content in the mice serum; in addition, the accumulation of lipid droplets in liver and the liver damage of hyperlipidemic mice were significantly attenuated. The diet with high polydextrose snack generated hepatoprotective and hypolipidemic effect on the hyperlipidemic mice. The obtained results would contribute to development in healthy food product as well as green processing for industrial application.

iii ACKNOWLEDGMENT I wish to acknowledge the guidance and assistance of the following throughout this research project: Prof. Le Van Viet Man (supervisor), Ho Chi Minh City University of Technology PhD. Tran Thi Thu Tra, Ho Chi Minh City University of Technology PhD. Tran Gia Buu, Institute of Biotechnology and Food Technology, Industrial University of Ho Chi Minh City PhD.

Tran Thi Thanh Truc, Ho Chi Minh City University of Social Sciences and Humanities Do Thi Tuong Vy, Vice Production manager of snack team, Orion Food Vina., LTD Tran Bao Quynh, Food safety center, Orion Food Vina., LTD iv CONTENT CONTENT.v LIST OF TABLES. viii LIST OF FIGURES .x LIST OF ABBREVIATIONS. Production line of snack food with high fiber content. Materials for production of snack with high fiber content.

Commercial dietary fibers. Palm olein oil. Sugar and salt. Transformation of food materials during extrusion.

Changes in lipids. Changes in protein. Changes in starch. Changes in dietary fiber.

Chemical and physico-chemical changes. Biological and biochemical changes. Effects of fiber types on extrudate quality. Physical and physico-chemical properties.

Transformation of food materials during frying. Effects of antioxidants on the frying product and oil quality. Extruded snack with high fiber content. Novelty of this study.

Chemical for analysis. Classic experimental design. In vivo experiment. Section 1: Use of commercial fiber preparation in the snack extrusion for improvement in the fiber content .1: Effects of various commercial fiber preparations on the snack quality .2: Effects of fiber preparation ratio in the mixing blend on the snack quality .3: Effects of extrusion screw speed on the snack quality 40 3.4: Effects of barrel temperature on the snack quality.

Section 2: Use of commercial natural antioxidants in the frying of the extruded corn snack .1: Effects of natural antioxidants on the frying oil quality during the heat treatment .2: Effects of antioxidant concentration in the frying oil on the oil quality during the heat treatment.3: Effects of natural antioxidant on the quality of oil in the fryer and in the fried snack during the repeated batch frying. Section 3: Healthy benefits of corn snack food with high polydextrose content - Vivo test. Chemical analysis for materials and extrudates. Chemical analysis for palm olein.

Physical analysis for extrudates. Physico-chemical analysis for extrudates. In vivo test on mice model. Serum biochemical parameters.

Histopathologic studies of liver. Use of commercial fiber preparation in the snack extrusion for improvement in the fiber content. Effects of various commercial fiber preparations on the snack quality. Effects of fiber types on chemical composition of the extrudate.

Effects of fiber types on physical properties of the product. Effects of fiber types on sensory score of the product. Effects of polydextrose ratio in the mixing blend on the snack quality. Effects of polydextrose ratio on chemical composition of the extrudate 65 4.

Effects of polydextrose ratio on physical properties of the extrudate. Effects of polydextrose ratio on sensory score of the product. Effects of extrusion screw speed on the snack quality. Effects of extrusion screw speed on approximate composition of the fried extrudate.

Effects of extrusion screw speed on physical properties of the fried extrudate. Effects of extrusion screw speed on sensory score of the fried extrudate74 4. Effects of extrusion screw speed on instrumental color, water absorption index, water solubility index of the fried extrudate and specific mechanical energy of the extrusion process. Effects of extrusion temperature on the snack quality.

Effects of extrusion temperature on the chemical composition of the extrudate. Effects of extrusion temperature on the physical properties of the extrudate. Effects of extrusion temperature on sensory score of the fried extrudate80 4. Effects of extrusion temperature on instrumental color, water absorption index, water solubility index of the fried extrudate and specific mechanical energy of the extrusion process.

Use of commercial natural antioxidants in the frying of the extruded corn snack84 4. Effects of natural antioxidants on the palm olein oil quality during the heat treatment. Effects of nutmeg concentration on the palm olein oil quality during the heat treatment. Effects of nutmeg oil on the palm olein oil quality during the extrudate frying.

Hypolipidemic and hepato protective effects of high polydextrose extruded corn snack on swiss albino mice. Feed and energy intake. Effects of high polydextrose snack on body weight. Effects of high polydextrose snack on the lipid profile serum parameters of the mice.

Effects of high polydextrose snack on liver function. Effects of high polydextrose snack on fat accumulation and liver structure .107 vii LIST OF TABLES Table 2. Corn products defined by particle size and fat content (Gwirtz & Garcia- Casal, 2014). Composition of dry-milled corn grits (Nor et al.

Components of dietary fiber according to the AACC (2001). Preparations containing dietary fiber (% w/w on dry basis) used in extruded snack food. The origin, chemical structure, technological properties and applications of commercial dietary fibers to food industry are listed. Nutritional benefits of high fiber content extrudates.

Physical and chemical changes in food during the frying process (Pokorny, 1998). Main groups of compounds formed in oil during the frying process (Bordin et al. Chemical and physical property of palm olien oil *. Dietary fibers used in the study and their approximate composition (g/kg).

Natural and synthetic antioxidants *. Chemicals used in the study, their purity and producers. The mixing formula for the mice feeding. Approximate composition (calculated on % dry weight basis) of each diet gr oup.

Tools & equipments used in the experimental analysis. Effects of fiber types on chemical composition (g/kg) of the fried extrudatea. Effects of fiber types on physical properties of the fried extrudatea. Effects of various fiber types on color of the fried extrudatea.

Effects of polydextrose content on chemical composition (g/kg) of the fried extrudatea. Effects of polydextrose content on physical properties of the fried extrudatea. Effects of polydextrose content on color of the fried extrudatea. Effects of extrusion screw speed on approximate composition (g/kg) of the f ried extrudatea.

Effects of extrusion screw speed on physical properties of the fried extrudatea. Effects of extrusion screw speed on instrumental color of the fried extrudate and specific mechanical energy (SME) of the extrusion processa. Effects of extrusion temperature on chemical composition (g/kg) of the frie d extrudatea. Effects of barrel temperature on physical properties of the fried extrudatea.

Effects of barrel temperature on Color & SME of the fried extrudatea. Quality changes in palm olein oil during the heat treatmen with various antioxidants. Effects of nutmeg content in palm olein oil during frying process. 92 ix LIST OF FIGURES Figure 2.

Production line schema of snack food processing (Moscicki & Van Zuili chem, 2011). Screws in a twin-screw extruder (Moscicki & Van Zuilichem, 2011). Continuous frying system (Heat & Control. Flow chart of snack production.

Scanning electronic micrographs of the fried extrudate with various fiber sources: a) Control, b) Polydextrose, c) Xanthan gum, d) Gum acacia, e) Inulin, f) Resistant starch, g) Resistant maltodextrin. Effects of fiber types on sensory score of the fried extrudate. Scanning electronic micrographs of the fried extrudate with various poly -dextrose contents. The polydextrose content (% of dry weigh basis) in the blend was: A) 0; B) 2,5; C) 5; D) 7,5 and E) 10,0 %.

Effects of polydextrose content on sensory score of the fried extrudate. Scanning electronic micrographs of the fried extrudate on screw rpm variables: a) 150rpm, b) 160rpm, c) 170rpm, d) 180rpm e) 190rpm. Effects of extrusion screw speed on sensory score of the fried extrudate. Effects of extrusion screw speed on water absorption index (WAI) and water solubility index (WSI) of the fried extrudate.