Metabolic Availability of Methionine in Tempeh Chips Among Reproductive-age Women Using Indicator Amino Acid Oxidation (IAAO) Method

The goal of this study is to determine the protein quality of soybean tempeh in the form of chips. The main objective of this study is to determine how much methionine in tempeh can be used by reproductive-age women using the stable isotope method. The tempeh will be studied in the form of chips. This research is being done to bridge the gap between the knowledge of protein requirements and the amount of food needed to meet those requirements. Results from this study will be important to confirm the protein quality of tempeh and thus provide a new alternative good protein source for humans, especially vegetarians and those with low socioeconomic status. Each participant will undergo seven experimental trials randomly. During four experimental trials, methionine intake will be obtained from a crystalline amino acid mixture, and during another three experimental trials, it will be obtained from tempeh chips. Each experimental trial will take three days, consisting of two adaptation days and one study day. During the two adaptation days, four equal meals per day will be consumed by the participants at their own place. On the study day, participants will need to come to the research unit of the National University of Malaysia, Kuala Lumpur campus, to consume nine hourly meals. In addition, during the study day, participants will also need to have their breath samples collected, their expired carbon dioxide rate measured, and consume a stable isotope.

Inclusion Criteria: * Universiti Kebangsaan Malaysia Kuala Lumpur campus female students and staffs aged 19 - 30 years old * Malaysian * Have consistent weight in the past 6 months * Have a normal body fat percentage (20% - 29.9%) Exclusion Criteria: * Pregnant women * Lactating women * Reported serious medical or surgical ailments 3 months prior to start of the study * On dietary or nutrient supplements or who had taken antibiotics 4 weeks before the initiation of the study * Smoking * Allergy to soybean * Excessively high protein intake in the past 6 months