investigation on the effects of different amounts of gellatin and guar on texture, organoleptic and color properties of white mulberry pastille

introduction: morus alba, known as white mulberry, is a short-lived, fast-growing and small to medium sized mulberry tree, which grows to 10–20 meters tall. the species is native to northern china, and is widely cultivated and naturalized elsewhere. the fruit is 1–2.5 cm long in the species in the wild, it is deep purple, but in many cultivated plants it varies from white to pink, being sweet and bland. the fruits are also eaten, often dried or made into wine or vinegar. in traditional chinese medicine, the fruit is used to treat prematurely grey hair, to tonify the blood, and treat constipation and diabetes. white mulberry is a fruit with high nutritional quality. the shelf life of mulberry is short due to its high moisture content. dried mulberry and its molasses are popular products from mulberry fruit. hydrocolloids are used in fruit snacks formulations to create novel texture, increase stability for their water-holding capacity, improve texture and have an impact on flavor release and other structural and sensory properties in the respective products. hydrocolloids are also widely used in the food industry as thickeners, stabilizers and gelling agents in various products including ice cream, sauces, jellies and pastille products. guar gam is kind of long-chain galacto-mannan with high molecular weight, obtained from endosperm of guar plant. this type of synergistic behavior among polysaccharides is commercially valuable, because it creates a novel texture and a more desirable structure. the aim of this research is to produce mulberry pastille as a novel and value added product with long shelf life. beside it can be introduced as a healthy snack replacing sugar. materials and methods: the materials include mulberry puree, hydrocolloids (gelatin and guar) and citric acid. berries were collected from the gardens around mashhad (iran). guar was purchased from sigma chemical company, citric acid was purchased from merk chemical company, germany. gelatin (0, 1, and 2 %) and guar (0, 0.5, and 1 %) were used for pastille formulations. to produce fruit pastille based on mulberry puree, the prepared puree was mixed into hydrocolloids. after measure ph and moderating to ph = 4.3 by adding acid citric in 40 % concentration and controlling the brix degree to constant brix of 45, the mixture was prepared. then the prepared mixture was poured into a network framework of steel origin in the cavities with 1.2×1/2 and the molds were hold in the refrigerator for 2 hours with 4°c to fasten the gel. the obtained gel was taken out of the mold cavities and placed in a glass plate. the samples were then dried at 70° c in a hot air drier with airflow rate of 1.5 m/s for 6 hours. the samples were evicted every 30 minutes. parameters such as color, sensory and textural characteristics of samples were investigated. statistical design was 2 factors factorial with three replicates adopted completely randomized design. results and discussion: the results of texture evaluation showed that increasing guar gum improves the cohesion, elasticity and chewiness of the samples, while their adhesion were decreases. conclusion: mulberry pastille including 1% guar and 1% gelatin having the lowest amount of firmness, adhesion, chewiness and suitable color characteristics, was determined as the best formulation among the other investigated samples.