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Hydroxyapatite (HAp, Ca10(PO4)6(OH)2) is the most stable form of calcium phosphate and widely used in various medical applications, mainly in orthopedics and dentistry due to its close similarities with the inorganic mineral component of bone and teeth. This study aims to synthesize hydroxyapatite from duck eggshell using the precipitation method. The duck eggshell was calcined, hydrated (slaking) and underwent carbonation to form Precipitated Calcium Carbonate (PCC).  Afterwards, (NH4)2HPO4 was added to produce HAp by varying the molar ratio of Ca/P by 1.67, 1.77 and 1.87 and stirring speed by 200, 250, 300rpm under basic condition (pH 10 – 11). The best results were obtained at a molar ratio of 1.77 with 200rpm stirring speed. Furthermore, the X-ray Diffraction (XRD) analysis showed that its crystals were hexagonal with sizes of 23.062nm, in the absence of other crystalline phases. Therefore, the hydroxyapatite was obtained in the agglomerates form with a specific surface area of ??55.929m2/g.

Doughnuts are one of the most popular sweet foods for people of all ages around the world. Although made from simple ingredients such as flour, sugar, eggs, yeast, milk powder, salt, water, and margarine, however producing doughnuts requires special techniques to produce good-quality doughnuts. It needs more energy, even physically and electrical equipment. A workshop on doughnut production with autolyze method for Dharma Women Association, Faculty of Engineering, University of Riau, was conducted to increase the knowledge and skills of members of the organization in making healthy dishes for the family. In this workshop, doughnuts were made using the autolysis method, which is mixing bread flour with water and then keeping the dough until gluten was formed. The formation of gluten is one indicator of the formation of smooth, soft, and elastic dough. The workshop results showed high interest among the Dharma Women Association members in making doughnuts with this alternative method.

Liquid waste from processing cassava into tapioca starch is carbohydrate-rich waste and can be used as a growth medium for the Acetobacter xylinum, which is useful in producing one of the fermentation products, i.e. nata. Several factors influence the production of nata, one of them is the addition of nutrients in the form of nitrogen in the fermentation medium. The nitrogen source used is usually from inorganic fertilizers, such as urea and ammonium sulfate. In this study, fermentation of tapioca starch wastewater was developed, using a natural sources of nitrogen derived from soybean and green bean sprouts extract. Nata was made by treating various concentrations of soybean and green bean sprouts extract (3%, 4%, 5%) and fermentation time (6 days, 7 days, 8 days, 9 days and 10 days). The characteristics of the nata product were seen from the thickness and yield of the nata. The nata de cassava product's optimum results were tested for thickness, yield, and moisture content. The results showed that the best type of natural nitrogen source was soybean sprouts extract 5%, fermentation time of 10 days with a thickness of 0.55 cm, the water content of 97.58%, and yield of 63.09%