Increasing resistant starch content in fish crackers through various cooking-chilling conditions

Fish cracker is one of the favourite snacks in Malaysia. However, studies on resistant starch (RS) in it have been paid little attention. Resistant starch is a starch that goes through the small intestine without being digested, providing a similar effect as dietary fibre. This RS can potentially be formed during the cooking and chilling processes in the production of the fish cracker. Both processes involve starch gelatinization and retrogradation that can lead to the formation of RS, creating a healthy and valuable product. Thus, this work investigates the effect of varying cooking-chilling conditions on resistant starch (RS) content and other important quality characteristics in fish cracker products. Process conditions such as the number of repetitive cooking-chilling (RCC) cycles (1 to 4 cycles), cooking temperature (100 °C, 115 °C and 121 °C) and chilling duration (1 to 4 days) as well as the type of starch used in the formulation (tapioca, wheat and sago) were studied with the aim to enhance the fish crackers with an appreciable amount of resistant starch without compromising the quality characteristics. The quality characteristics of fish crackers in terms of hardness and moisture content of the chilled fish cracker gels, the RS of the dried fish crackers as well as the linear expansion (LE), hardness and colour of the fried fish crackers were evaluated. The results showed that up to four cycles of RCC increased the RS content in all products. Sago starch fish crackers cooked at 121 °C had the highest RS content in the dried samples. The repeated cooking-chilling cycles increased the extent of starch gelatinization with each successive cooking cycle and promoted retrogradation upon cooling, thus, promoting the formation of RS. However, initially cooking the fish crackers at 100 °C and exposing to a longer chilling duration of up to four days did not demonstrate any changes in the RS. Different combinations of cooking-chilling repetition, cooking temperatures and chilling durations produced varying RS content in the fish crackers. As for other quality characteristics, increasing the RCC cycles produced chilled fish cracker gels that were less hard and had higher moisture content. Longer chilling durations gave the opposite results. The quality characteristics of the fried fish crackers, namely hardness and colour, were mostly dependent on their expansion ability during frying. Fish crackers containing a higher RS have a lower LE with a negative correlation of R2 = -0.777, thus, fried products with a lower LE were higher in hardness values and darker in colour The findings of the present study demonstrated that the variations of cooking-chilling conditions were able to increase the RS content in fish crackers. The lab-produced fish crackers in this study were superior in RS content with an acceptable range of LE and hardness values compared to the commercial non-fried and instant fish crackers. Thus,the lab-produced fish crackers in this study offer better health benefits in term of RS with comparable LE and hardness values for the consumer

Physical and Chemical Characterization of Manalagi Apple (Malus sylvestris Mill) Leather Enriched with Either Mango, Pineapple or Dragon Fruit

Manalagi apple leather can be an innovation for new processed products made from fruit pulp and undergo a drying process. The main problem is that apple leather has a less plastic texture, non-variative color and taste, and stickiness. For this reason, in this study other fruits were added in certain proportions and food additives such as arabic gum and maltodextrin to improve the physicochemical and organoleptic characteristics of manalagi apple leathers. This study used the Split-split Plot Design method with three factors. Factor I is a type of fruit (red dragon fruit, pineapple, mango), factor II is the variation in proportion ((25:75)%, (50:50)%, (75:25)%), factor III is maltodextrin concentration (5%, 10%, 15%). The best treatment was taken from each type of fruit substitution, so there were 3 the best treatment: apple leather 1) enriched with 50% dragon fruit and 10% maltodextrin; 2) enriched with 75% pineapple and 10% maltodextrin, and 3) enriched with 75% mango and 10% maltodextrin.DOI: 10.17977/um024v7i22022p11

Drying, colour and sensory characteristics of ‘Berangan’ banana (Musa accuminata) flesh dried using a microwave oven

The drying characteristics of ‘Berangan’ banana flesh dried under microwave heating were studied in this work. The produced microwave banana chip was then compared with the conventional deep oil fried banana chip in terms of colour and sensory characteristics.‘Berangan’ banana slices with 3 mm thickness were dried using microwave at three power levels of 100, 440 and 1000 W. Shorter drying times were obtained when higher microwave power was applied during drying, where the drying times were found to be 30, 7, 4 min at 100, 440 and 100W. Three different drying models were used to describe the resulting drying curves. The drying rate constant increased from 0.298, 0.4211 and 0.2977 min-1 to 1.8717, 1.9956 and 1.8936 min-1 for the Newton, Page and Henderson and Pabis models when the microwave power used was increased from 100W to 1000W. The best model to represent the drying data obtained in this work was found to be the Page model. In terms of colour, fried banana had a browner, duller colour than microwave dried banana. For sensory evaluation, dried banana chips using microwave at a power level of 440W was the most preferable. It can be concluded microwave dried banana chips showed better results than fried banana chips in terms of colour and sensory characteristics in the range tested in this study

Application of membrane-based technology for purification of bromelain

About 60% of world’s commercial enzyme products are proteases, giving promising opportunity to derive such enzymes sustainably from waste sources. Bromelain is a crude protease occurring naturally in pineapple, and it possesses properties of benefit for pharmaceutical, medical and food products. The production of bromelain involves a purification stage, normally performed by small-scale conventional operations which lead to high operating cost and low product recovery, while being difficult to scale up and produce polluting by-products. Membrane-based technology offers an alternative to produce high quality purified bromelain in a more efficient and sustainable process. This review identified the current state and future needs for utilising membrane processes for sustainable bromelain production at larger scales. It was found that declining membrane flux due to fouling have been reported, but may be effectively overcome with more appropriate (and advanced) membrane types and/or processing conditions. For example, interactions between macromolecules present in the pineapple derived bromelain mixture (particularly polysaccharides) and the membrane may cause performance limiting fouling, but can be overcome by enzymatic pre-treatment. Membrane fouling can be further reduced by the employment of ceramic membrane filters operating at optimised trans-membrane pressure, cross-flow velocity, feed pH and temperature. Two-stage ultrafiltration together with diafiltration or gas sparging was suggested as a means to reduce fouling and improve enzyme purity. Despite these promising technical findings, the review identified the need for a valid economic assessment to properly guide further work towards purifying bromelain from pineapple waste for sustainable production of commercial proteases

Mechanical analysis of a wedge device in sawing technology

The oil palm trunk (OPT) currently represents a massive volume of agricultural waste with great potential to be rapidly developed in the wood composite industry. An improvement in sawing technology has potential to improve the yield of the commercially hard outer core of the OPT by about 27 % thus replacing the present sub-optimal square sawing pattern with a more efficient and higher-yielding polygon sawing pattern. To achieve this, a 'wedge' device was designed to be mounted on the existing sawing carriage. The proper methodology was followed including extraction of the design layout of the machine, development of the schematic drawing and wireframe model, modification of the design in computer-aided design (CAD) environment, the performance of stress, total deformation, and fatigue analysis, and production of a complete drawing for fabrication purpose. Results from the analysis showed that the designed part was safe to be fabricated with a small maximum equivalent stress of 2.546 MPa, maximum total deformation of 0.007935 mm and total life cycle of one million cycles. These evaluation results indicate that the material used for the wedge device (including the base part) satisfies the design requirements of static strength and is safe within its designed fatigue life

Effects of cooking temperature in repetitive cooking-chilling cycles on resistant starch content and quality characteristics of fish crackers

This work describes the effects of different cooking temperatures in repetitive cooking-chilling (RCC) process on resistant starch (RS) content in fish crackers prepared in a ratio of 1:1 fish to sago starch formulation. In this work, three sets of four RCC cycles were performed on fish crackers, in which each set was cooked at fixed temperatures of 100, 115 and 121°C, respectively. The chilling temperature was fixed at 4°C in all cases. Subjecting the fish crackers to a higher cooking temperature for up to 4 cycles of RCC can increase the RS content. However, quality degradation was observed in the characteristics of the fish crackers. During the first RCC cycle, cooking at a higher temperature had caused the crackers to crack and burst. Besides, defragmentation to the shape of the fish cracker gels was also observed during the first RCC cycle, coupled with softer texture and high moisture content. When the products were subjected to frying, their linear expansion decreased, the texture became harder and the colour turned darker. This work demonstrated that the application of higher cooking temperature up to 4 RCC cycles was able to enhance the RS content in the fish crackers, but it was less able to attain the product’s perfect shape. On the contrary, fish crackers that were exposed to lower cooking temperatures contained lower RS but with less shape damage

Physical properties of kelulut honey emulsions with different oil types and emulsifier concentrations

Kelulut honey (KH) is a honey produced by stingless bee species, known for its high nutritional content and health benefits. Even though it is very healthy, some people cannot consume it directly. Therefore, incorporating this type of honey into an emulsion system is a good strategy to increase its consumption. Emulsion technology is one of the alternative technologies nowadays which combines two or more immiscible liquids to form a solution. In this study, KHemulsions were emulsified with glyceryl monostearate (GMS) and stabilised by xanthan gum. There were two stages involvedto determine the effects of variations in oil types and emulsifier concentrations on the physical properties of KH emulsions. In the first stage, three types of oil were used as the dispersed phase, which were palm oil, canola oil, and sunflower oil. Then in the second stage, different concentrations of GMS (0.25, 0.5, 0.75 and 1%) were applied. From the droplet size analysis, the emulsion with sunflower oil and the highest concentration of GMS gave the smallest diameter of 0.78 ± 0.01µm and the lowest polydispersity index (pdI) of 16.2±2.03 %. Meanwhile, the texture analysis shows that emulsion with palm oil has the highest firmness (45.16±2.83 g) and consistency (305.44±14.91 g.sec) values. The foaming index on the other hand depicts that emulsion with palm oil and that with the lowest concentration of GMS gave the highest foam stability. From this study, a physically stable oil-in-water KH emulsion was produced, which should undergo further chemical, sensory and storage studies for commercial production in the future

FIZIKALNA TERAPIJA U SVJETLU BIOLOŠKE TERAPIJE I TERAPIJE MALIM MOLEKULAMA

Membrane technology has been successfully applied for the purification of bromelain, a protease enzyme from pineapple. However, the current system operates less optimally in terms of flux and separation primarily due to properties of the feed, such as viscosity. Hence, in this study, enzymatic pretreatment and diafiltration operation were employed in a two-stage ultrafiltration (UF) system to enhance the performance of the purification and concentration process of bromelain enzyme from an extract of pineapple crude waste mixture (CWM). Pretreatment of the CWM extract using either pectinase or cellulase, or the combination of both, was applied and compared regarding the apparent viscosity reduction. Diafiltration step was introduced in UF stage 2 and observations on the flux performance, enzyme recovery and enzyme purity were made. A 12% apparent viscosity reduction was achieved when the CWM extract was pretreated with pectinase which led to 37-38% improvement in the flux performance of both UF stages, as well as higher enzyme recovery in UF stage 1. The introduction of diafiltration mode in UF stage 2 managed to sustain high flux values while yielding 4.4-fold enzyme purity (higher than a 2.5-fold purity achieved in our previous work); however, high diluent consumption was needed. The outcomes of this study showed that the flux performance and bromelain separation can be enhanced by reducing the viscosity with the employment of enzymatic pretreatment and diafiltration operation. Thus, both techniques can be potentially applied in a large-scale membrane-based process for bromelain production

Optimizing the processing factor and formulation of oat-based cookie dough for enhancement in stickiness and moisture content using response surface methodology and superimposition

Despite the utilization of dusting flour and oil to reduce dough stickiness during the production process in food industry, they do not effectively help in eliminating the problem. Stickiness remains the bane of the production of bakery and confectionery products, including cookies. In addition, the high moisture content of cookie dough is unduly important to obtain a high breaking and compression strengths (cookies with high breaking tolerance). This study was conducted in light of insufficient research hitherto undertaken on the utilization of response surface methodology and superimposition to enhance the stickiness and moisture content of quick oat-based cookie dough. The study aims at optimizating, validating and superimposing the best combination of factors, to produce the lowest stickiness and highest moisture content in cookie dough. In addition, the effect of flour content and resting time on the stickiness and moisture content of cookie dough was also investigated, and microstructure analysis conducted. The central composite design (CCD) technique was employed and 39 runs were generated by CCD based on two factors with five levels, which comprised flour content (50, 55, 60, 65, and 70%), resting time (10, 20, 30, 40, and 50 min) and three replications. Results from ANOVA showed that all factors were statistically significant at p < 0.05. Flour content between 56% and 62%, and resting time within 27 and 50 min, resulted in dough with high stickiness. High-region moisture content was observed for flour content between 60% and 70%, and within 10 and 15 min of resting time. The optimized values for flour content (V1) = 67% and resting time (V2) = 10 min. The predicted model (regression coefficient model) was found to be accurate in predicting the optimum value of factors. The experimental validation showed the average relative deviation for stickiness and moisture content was 8.54% and 1.44%, respectively. The superimposition of the contour plots was successfully developed to identify the optimum region for the lowest stickiness and highest moisture content which were at 67–70% flour content and 10–15 min resting time

Mass transfer with reaction kinetics of the biocatalytic membrane reactor using a fouled covalently immobilised enzyme layer (α–CGTase–CNF layer)

A dynamic mathematical model was used in this study to describe the mass transfer and reaction kinetics of a fouled α–CGTase–CNF layer in a biocatalytic membrane reactor (BMR) system. BMR performance was evaluated based on the effect of substrate concentration and pneumatic gauge pressure on the permeate flux, total permeate volume, starch conversion, and α-CD production. A model is introduced based on the layer of mass limit as the resistance blocking mechanism with reaction kinetics on the fouled α–CGTase–CNF layer. Important unknown parameters of the constants describing the layer resistance, KML0 and the kinetic constant of Michaelis-Menten, kcat, for mass transfer and its reaction kinetics, were successfully estimated at 3.9 × 107 min/mL and 216.18 mg-starch/cm3⋅U⋅min, respectively, using the proposed models. The study found that the kcat value corresponding to the maximum efficiency of the enzyme on starch cyclisation was a critical parameter in the prediction of the BMR dynamic profiles. Thus, the proposed model in this study can be used for further development of the BMR system, with excellent hydrodynamic and reaction performance