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Abstract. Indrati R, Handayani MT, Rahayu NA, Pebrianti SA. 2021. Effect of legume varieties and fermentation time of tempe using usar inoculum on the inhibitory activity of angiotensin I-converting enzyme. Biodiversitas 22: 5262-5267. The effect of three varieties of legumes, namely, velvet bean (Mucuna prurient), lima bean (Phasaelus lunatus L.), and pigeon pea (Cajanus cajan), on the activity of angiotensin I-converting enzyme (ACE) inhibitors was studied during tempe fermentation. Fermentation is one way to produce bioactive peptides. Furthermore, the effect of inoculum usar on tempe fermentation was studied. Hydrophobic amino acids are essential in binding firmly to the active site of ACE, and the research showed that pigeon pea had higher levels of hydrophobic amino acids compared with soybeans. The legumes affected the protease activity, peptide content, degree of hydrolysis, and production of ACE inhibitory (ACEI) activity during tempe fermentation. High protein levels and peptide content did not guarantee a high ACE inhibitor level. The mixed culture of usar caused no effect on the production of ACE inhibitors compared with a single culture of Raprima. Legume beans that reached optimal fermentation fast produced high levels of ACE inhibitors. Of the three types of legumes tested in the study, lima beans had the highest ACEI activity during fermentation.

Tempeh is a fermented food that is good for health and has high nutritional value. Koro kratok tempeh is one of tempeh which is made from non-soybean legumes. The fermentation process will convert macromolecular compounds to micromolecules thereby increasing bioavailability and providing functional properties. This study aimed to find out the chemical properties of koro kratok tempeh and the effect of peptide molecular weight of koro kratok tempeh on ACE inhibition activity. The results show that koro kratok seeds contained 20.66% protein which total hydrophobic amino acid was 3.32% (w/w protein). This hydrophobic amino acid was higher than that soybean, indicated that koro kratok (Phaseolus lunatus) has a potential producing ACE peptide inhibitors. The koro kratok seeds had ACE inhibitory activity  19.72%. This activity increased to 84.97% when the seeds were fermented for 48h to become tempeh. Peptide fractionation showed that the smaller the molecular weight of the peptide, the higher the ACE inhibitory activity.

Koro kratok fermentation used Rhizopus oligosphorus was one of Indonesian’s society methods to consumed Koro kratok. Rhizopus oligosphorus produced proteolytic enzyme which can be used to break down complex protein to simple protein. Protein degradation was observed based on the fermentation time of koro kratok. Fermentation times used were 0 hours, 12 hours, 24 hours, 36 hours, 48 hours, 72 hours, 96 hours and 120 hours of fermentation. Parameters observed included proteolytic activity, growth of Rhizopus oligosphorus mycelium, dissolved protein, protein concentration and degree of hydrolysis also protein pattern using SDS PAGE. Observation showed that proteolytic activity, Rhizopus oligosphorus mycelium growth, dissolved protein, protein concentration and degree of hydrolysis were directly proportional to the length of fermentation time. The results of observation on protein patterns using SDS PAGE show that the longer the fermentation time, the simpler the protein produced. The longer the fermentation time, the bigger protein degration of koro kratok.

Weaning food is given as a complement to breast milk which is helpful for babies in the process of baby led weaning. At six months, the baby's digestive tract is able to digest some  food such as flour so baby can be introduced to solid food. Purple sweet potato has good nutrition such as carbohydrates, protein, fat, vitamins, minerals, and water. Ultrasound modification is considered easier, simpler, and safer because it does not use chemical additives. This research used a non-factorial completely randomized design (CRD) with one variable treatment and three replication. The variable was  the ratio of sweet potato ultrasound modified starch and rice flour (0%:100%; 20%:80%; 40%:60%; 60%:40%; 80%:20%; 100%:0%).  The result showed the ratio of sweet potato ultrasound modified starch and rice flour had significant effect on the chemical properties of instant weaning food.  The significant result was shown by formulation of sweet potato ultrasound modified starch 100%  and rice flour 0%  with moisture content 3.88%, ash 0.69%, protein 16.87%, fat 1.66%, and carbohydrates 76.88%.