Physicochemical characterization and value-added extrusion processing of fiber-rich food processing byproducts

Increasing consumer demand for high fiber food products present the opportunity for the utilization of fiber-rich food processing byproducts as value-added ingredients. These low-cost nutritious ingredients are available in abundance, yet underutilized as food ingredients. Their composition varies significantly across sources, and thus their physicochemical properties, that can impact the characteristics of food products into which they are incorporated. This emphasizes the importance of characterization of their composition and physicochemical properties to understand their potential uses in foods, which was the first objective of this research. Eight byproducts from different sources (blueberry, cranberry, Concord grape, and apple pomaces; oat hull; sugarcane bagasse; pea hull; and potato skin) were analyzed and found to have significantly different composition and physicochemical properties. Three different clusters of these byproducts based upon their composition and physicochemical functional properties were obtained. This enabled us to assign ingredients in each cluster to potential end-uses. The inclusion of fiber-rich food processing byproducts in extruded snacks has posed a great challenge with the reduced expansion and thus poor textural quality of the extrudates enriched with fiber. This has led to lower consumer preference. Hence, the present study was aimed on exploring the potential of inclusion of fiber-rich byproducts in extruded snacks by evaluating the expansion characteristics of extrudates. Extrusion with varying screw speeds (150-250 rpm) was conducted in combinations of waxy and regular cornstarch with apple pomace and sugarcane bagasse in varying inclusion levels (0-30% w/w). Extrusion process responses and product responses were assessed. Higher initial and stable expansions were observed with apple pomace but also higher shrinkage compared to sugarcane bagasse. Inclusion of 15% w/w of apple pomace produced higher initial (4.24-5.38) and stable expansions (3.88-4.43) than control (3.90-4.54 and 3.82-4.27, respectively), with lower mechanical energy. This suggests the potential for apple pomace inclusion in puffed extrudates to obtain high quality products if the post-processing conditions can be controlled to avoid product shrinkage, providing opportunities for the food industry to produce high fiber extruded snacks with acceptable textural quality

UTILIZATION OF RESPONSE SURFACE METHODOLOGY IN THE OPTIMIZATION OF ROSELLE ICE CREAM MAKING [Penggunaan Response Surface Methodology dalam Optimisasi Pembuatan Es Krim Rosella]

This research was carried out to develop functional ice cream product with natural colorant derived from the optimum set of roselle calyces extract and citric acid levels. Although citric acid can improve red color stability of rosella, its addition is limited due to the acidic and bitter aftertaste it imparts. Response surface methodology (RSM) was employed to analyze the effect of roselle calyces extract and citric acid on the physico-chemical characteristics and sensory acceptance of ice cream. A central composite design consisting of two independent variables (roselle calyces extract and citric acid levels) in a five levels pattern (-1.41421, -1, 0, +1, and +1.41421) with 13 runs (formulations) was prepared to establish the optimum set of variables. Higher concentration of roselle calyces extract significantly increased the total anthocyanin content and color acceptance, while decreased the ºHue and pH of ice cream. Higher concentration of citric acid significantly increased the overrun and color acceptance, but decreased the viscosity, ºHue, pH, texture, taste acceptance, and overall acceptance of ice cream. The optimum scores of consumer sensory acceptance were met at 11.5% roselle calyces extract and 1.5% citric acid levels