Selection of dietary fibres for sucrose replacement in functional Chhana‐murki (Indian Cottage cheese‐based dessert) and their effect on sensory,physical and instrumental texture parameters

With a wide range of beneficial effects on human health, various dietary fibres such as microcrystalline cellulose (MCC), inulin, oat fibre and wheat fibre were screened based on their bulking ability in the functional Chhana‐murki (FCM) with respect to sensory and physical properties. Sensory scores were maximum for MCC at 7.5% having optimum moisture content and water activity and minimum hardness, whereas oat and wheat fibres increased the hardness of the product while decreasing the moisture content and water activity thus lowering the sensory scores. Further, replacement of MCC with inulin in 1:1 ratio improved the product characteristics.     

Optimisation of ingredients for a low‐fat,Chhana‐based dairy spread using response surface methodology

The effect of ingredients, viz. chhana, skimmed milk powder (SMP), maltodextrin and whey powder, on sensory and texture responses of a low‐fat chhana‐based spreads was studied and its formulation was optimised using response surface methodology. In linear and quadratic terms, chhana and SMP significantly influenced all the responses. The interaction term between maltodextrin and chhana was the most effective in influencing texture parameters. Optimisation suggested 55.6% chhana, 6.2% SMP, 4% maltodextrin, 2% whey powder, 1.5% edible salt, 1.5% enzyme‐modified cheese, 0.5% sodium tripolyphosphate, 0.5% trisodium citrate, 0.3% glycerol monostearate and 28% water with desirability of 0.889, as the best levels of these ingredients in a formulation that also contained 1.5% edible salt, 1.5% enzyme‐modi ed cheese, 0.5% sodium tripolyphosphate, 0.5% trisodium citrate, 0.3% glycerol monostearate and 28% water on a w/w basis.     

Influence of polysaccharides and storage during processing on the properties of mango seed kernel extract (microencapsulation)

Extracts from mango (Mangifera indica Linn.) cultivar Chok–Anan seed kernels were studied as active substances, since they are known as a good source of phenolic antioxidants with metal chelating and tyrosinase inhibitory activities. Response surface methodology (RSM) was used to investigate the effect of a combination of polysaccharides selected from gum arabic, maltodextrin and alginate on droplet size distribution, encapsulation efficiency (EE), stability and viscosity of W/O/W emulsions. In addition, the effects of stored emulsion on the properties of the encapsulated powder were studied. The results showed that there were interactions between polysaccharides which affected droplet size distribution, stability, viscosity and EE of multiple emulsions. The RSM showed a good fit to the proposed model with R² > 0.83, 0.79 and 0.69 for viscosity, stability and EE, respectively, with significant correlations (p < 0.05). The formulation which gave an optimal coating material was also a suitable coating mixture for preparation of encapsulated mango seed kernel extract powder. Moreover, if the polysaccharide combination is not appropriate for coating, the storage after emulsion preparation will have a greater effect on the properties of the encapsulated emulsion and powder.     

Optimisation of the microencapsulation conditions and physicochemical properties of enteric‐coated lactase microcapsules

Enteric double‐coated lactase microcapsules were developed, and the encapsulation conditions were optimised using response surface methodology. The optimum concentration of the enteric coating material was 4.85 g/100 mL, and the amount of core material was 1.85 mL. The particle size of the zein‐coated microcapsules was 2.868 μm, which was smaller than that of the other microcapsules. All microcapsules showed high zeta‐potential values between pH 6 and 8. The in vitro release rates of hydroxypropyl methyl cellulose phthalate (HPMCP)‐ and shellac‐coated microcapsules were superior to that of the zein‐coated microcapsules. Finally, the microcapsules were barely hydrolysed in simulated gastric fluid; however, almost all the microcapsules coated with HPMCP or shellac released their contents in simulated intestinal fluid within 2 h (93.23 and 97.27%, respectively).     

Optimisation of Bacillus cereus biofilm removal in the dairy industry using an in vitro model of cleaning‐in‐place incorporating serine protease

This article addresses a major hygienic issue in the dairy industry, namely biofilm removal. Response surface methodology was deployed to optimise Bacillus cereus biofilm removal conditions using serine protease. The currently practiced alkali cleaning‐in‐place (CIP) method was also optimised, and while the optimised protease CIP resulted in complete removal of biofilm cells, the reference CIP (with alkali) resulted in a reduction of 4.08 log biofilm cells/cm² and the optimised alkali CIP resulted in a reduction of ～4.92 log biofilm cells/cm². Furthermore, the amount of the biofilm matrix removed in the optimised protease CIP was significantly higher than that of alkali CIP. It was concluded that the optimised protease CIP has better applicability.     

Novel use of Acacia senegal (Super Gum™) and Anogeisus latifolia (Gatifolia SD) as functional ingredients in extruded snack products: Their role in manipulating product characteristics and modulating the potential glycaemic response of snack foods

Acacia senegal (in the form of Super Gum™) and Anogeissus latifolia (in the form of gum Gatifolia SD) were used in the manufacture of ready to eat extruded cereal snack products. Inclusions rates were 0, 5, 10 and 15% w/w replacement levels for wheat flour from a control recipe. The inclusion of Super Gum™ and Gatifolia increased product expansion and reduced product density compared to a cereal flour based control snack product. Inclusion of the gum materials also decreased the hardness of the snack products whilst increasing the crispiness of the product (number of fracture peaks recorded during axial compression of samples). Glucose area under the curve (AUC) measurements obtained using in vitro digestion procedures illustrated that the potential glucose release of snack products was reduced by more than 30% by the inclusion of Gatifolia and Super Gum™ at 15% w/w compared to the control sample. Such a reduction in potential glucose release was not dose responsive. These results illustrate a potential nutritional benefit of the utilisation of Gatifolia and Super Gum™ in the ready to eat snack food sector of the food industry.     

Optimisation of Novozym‐435‐catalysed esterification of fatty acid mixture for the preparation of medium‐ and long‐chain triglycerides (MLCT) in solvent‐free medium

Novozym‐435‐catalysed esterification of caprylic acid, capric acid and oleic acid with glycerol for the synthesis of medium‐ and long‐chain triglycerides (MLCT) in vacuum and solvent‐free system was investigated in this study. Response surface methodology with a three‐level, four‐factorial design was applied to optimise the enzymatic esterification for the synthesis of MLCT. The optimum conditions were as follows: reaction temperature 90 °C, 4.80 wt% enzyme load (relative to the weight of total substrates) and substrate molar ratio (fatty acids/glycerol) of 3:1 and 12.37 h. Under above‐mentioned conditions, Triglycerides (TG) yield, MLCT and the residual free fatty acids (FFA) content in the product were 93.54%, 72.19% and 4.21%, respectively. The content of caprylic acid, capric acid and long‐chain fatty acids of TG was 24%, 10% and 66%, respectively. Novozym 435 in the study showed no selectivity for the different fatty acids and also could be used 14 times without obvious loss of enzyme activity.     

Response Surface Methodology for the Optimization and Characterization of Cassava Starch‐graft‐Poly(acrylamide)

Response surface methodology (RSM) was employed for the synthesis of cassava starch‐graft‐poly(acrylamide) using ceric ammonium nitrate as free radical initiator. Concentration of acrylamide, concentration of ceric ammonium nitrate, reaction temperature and duration of reaction were optimized using a 4‐factor 3‐level Box‐Behnken design. The dependent variables were percentage grafting (%G) and grafting efficiency (GE). Second order polynomial relationships were obtained for %G and GE, which explained the main, quadratic and interaction effects of factors. The highest%G and GE obtained were 174.8% and 90.7%, respectively. The optimum values of parameters predicted through RSM were 20 g acrylamide/10 g dry starch, 3.3 g/L ceric ammonium nitrate, 180 min reaction duration and 45ºC temperature with a %G of 190.0. For GE, the predicted levels of factors for the optimum value of 90.8% were 17.5 g acrylamide/10 g dry starch, 4.1 g/L ceric ammonium nitrate, 180 min reaction duration and 55ºC temperature. The graft reaction was confirmed by FTIR analysis, where the absorption bands corresponding to the C=O stretching and N‐H bending of the –CONH₂ group were observed. Scanning electron microscopic studies on grafted starches revealed that the granular structure of the starch was affected by the reaction. X‐ray diffraction analysis showed that the crystallinity of starch was decreased as a result of grafting and the reduction was higher for the grafted starches with higher percentage grafting.     

Optimisation of the formulation for barley–milk composite‐based fermented drink

The effect of barley flour concentration, Lactobacillus plantarum NCDC344 (Lp344) and co‐culture (Streptococcus thermophilus 20) inoculum levels on the sensory quality, Lp344 count, β‐glucan content and viscosity of barley–milk composite‐based fermented drink was investigated. A central composite rotatable design of response surface methodology was used for optimisation of the formulation. Of the three formulation variables, barley flour concentration was found to be the most critical as it significantly affected overall acceptability, Lp344 count and β‐glucan content (P < 0.01). The optimised drink rated 7.80 on a 9‐point hedonic scale, and contained 8.59 log cfu/mL of Lp344 cells and 0.144 g/100 g of β‐glucan.     

Significant improvement for the functional properties of konjac glucomannan based on phase separation

Konjac glucomannan (KGM) serves as a stabiliser due to its high molecular weight and viscosity. However, these properties limit its addition in food products, especially in drinks. The main aim of this study was to improve the functional properties of KGM by a green and effective method, that is phase separation. It was found that increasing temperature accelerated phase separation of KGM/gum arabic mixture. KGM‐rich phase was characterised and its physical properties were investigated by different methods. Crystal property showed no significant changes after phase separation. Nevertheless, rheological properties indicated that the viscosities of samples after phase separation (FKGM) decreased dramatically. Their emulsifying capacities also improved. Moreover, the differences in molecular rearrangement at the oil–water interface were also studied by using interfacial rheology. These results suggested that FKGM with low viscosity had better interfacial properties, and thus may have potential applications as food ingredients.     

Optimisation of a solid-phase microextraction/HPLC/Diode Array method for multiple pesticide screening in lettuce

A new method was developed for the determination of 10 pesticides widely used in lettuce production (acetamiprid, azoxystrobin, cyprodinil, fenhexamid, fludioxonil, folpet, iprodione, metalaxyl, pirimicarb, and tolyfluanid) using solid-phase microextraction (SPME) and liquid chromatography (HPLC) with diode-array detection (DAD). The extraction performance of four different SPME coatings, polydimethylsiloxane (PDMS), PDMS/divinylbenzene (PDMS/DVB), carbowax/templated resin (CW/TPR), and polyacrylate (PA) was evaluated using an interface SPME–HPLC. CW/TPR fibre was selected as the most appropriate for the extraction of majority of these pesticides. Three variables (pH, NaCl% and extraction time) were considered key factors in the optimisation process. Interactions between these analytical factors and their optimal levels were investigated by response surface methodology based on central composite design. The method allowed the determination of azoxystrobin, cyprodinil, fenehexamid, fludioxonil, folpet, iprodione, and tolyfluanid in lettuce at concentrations between 0.8 and 25.6 mg/kg, i.e., bellow the maximum residues levels allowed for those compounds in lettuce. Lettuce samples that suffered pesticide treatments with folpet and fenehexamid were analysed during days to harvest to study the dissipation behaviour of the pesticides used. Concentration of folpet was 92.8; 53.4; 22.9; 17.9; 7.45; 1.85 mg/kg and concentration of fenhexamid was 158.1; 76.2; 31.0; 27.3; 7.24; 0.87 mg/kg, respectively for t₀, t₁, t₃, t₆, t₇, t₉ days, and not detected at t₁₄ days for the two pesticides.     

Process optimisation for a ready‐to‐serve breakfast smoothie from a composite milk–sorghum base

A composite milk and sorghum‐based smoothie containing varying levels of sorghum flour (2–4% w/w), sugar (9–11% w/w) and pectin (0.2–0.4% w/w) was optimised by response surface methodology on the basis of sensory (colour and appearance, flavour, consistency, sweetness and overall preference) and physical (viscosity, sedimentation and wheying off) attributes. Flour and pectin levels influenced the flavour, consistency, viscosity and sedimentation significantly. Sugar helped to increase the overall preference and had a positive correlation with sedimentation. An optimised smoothie composition of acceptable quality was obtained with 2.79% (w/w) germinated sorghum flour (GSF), 10.30% (w/w) sugar and 0.35% (w/w) pectin.     

Optimisation of solid state fermentation of potato peel for the production of cellulolytic enzymes

This paper analyses the effects of water content, temperature and time on the kinetic activity of cellulolytic enzymes produced during the solid state fermentation of potato peel, using Aspergillus niger. Three main analytical steps – analysis of variance, regression analysis and plotting of response surface – were performed to obtain an optimum condition for enzymatic activity. The statistical results indicated that the best activity time for enzyme CMCase (carboxymethylcellulase) is 82.88 h, with water content of 51.48% and temperature of 29.46 °C; for FPase (filter paperase), the best activity time is 80.62 h, water content of 50.19% and temperature at 30.00 °C; for xylanase, time is 81.92 h, water content is 50.72% and temperature is 28.85 °C. Pareto charts have shown that all variables were significant in enzymatic activity for CMCase and xylanase. On the other hand, FPase shows that time and temperature have significant effect for this response variable.     

Optimisation of production yield by ultrasound‐/microwave‐assisted acid method and functional property of pectin from sugar beet pulp

Response surface methodology was used to optimise pectin recovery from sugar beet pulp using ultrasound‐/microwave‐assisted acid method (UMAAM). The independent variables were microwave heating temperature, microwave heating time and solid‐to‐liquid ratio. From the results, the selected optimal conditions were 92 °C, 37 min, and solid‐to‐liquid ratio 1:30. Under these conditions, the yield and uronic acid content of the pectin (SBP1) was 26.16% and 75.38%, respectively. Compared with the sugar beet pectin (SBP2) extracted by traditional acid method, SBP1 showed a higher molecular weight, higher viscosity and emulsifying activity and stability. The possible reason was that the UMAAM could have had minimal change in the protein–polysaccharide complex structure of pectin, but significantly increased the length of polysaccharide chains compared with SBP2. These results suggested that UMAAM is an efficient method in extracting pectin and has the potential to be used in the sugar beet industry.     

Optimisation of hydrolysis conditions for the production of the angiotensin-I converting enzyme (ACE) inhibitory peptides from whey protein using response surface methodology

In the present research, the effect of process conditions on the angiotensin-I converting enzyme (ACE) inhibitory activity of whey protein concentrate hydrolysed with crude proteinases preparation from L. helveticus LB13 was investigated systematically using response surface methodology. It was shown that ACE inhibitory activity of the whey hydrolysates could be controlled by regulation of three process conditions (hydrolysis temperature, pH and enzyme to substrate (E/S) ratio). Hydrolysis conditions for optimal ACE inhibition were defined using a response surface model. E/S ratio at 0.60, pH at 9.18 and temperature at 38.9 °C were found to be the optimal conditions to obtain high ACE inhibitory activity close to 92.2% and DH of the whey protein was 18.8%.     

Enhancing the levels of 4‐vinylguaiacol and 4‐vinylphenol in pilot‐scale top‐fermented wheat beers by response surface methodology

Top‐fermented wheat beers are desired by consumers because of their distinctive clove‐like and phenolic aroma, in which two characteristic flavour substances, 4‐vinylguaiacol (4VG) and 4‐vinylphenol (4VP), are of vital importance. In this paper, the levels of 4VG and 4VP were the subject of an intensive and detailed investigation. The influence of wheat malt proportion, mashing‐in temperature, boiling time and fermentation temperature on 4VG and 4VP was studied by pilot‐scale brewing experiments using a 10 hL mashing vessel and 20 hL fermentation tanks. Response surface methodology (RSM) was used to explore the possibilities for enhancing the concentration of 4VG and 4VP in top‐fermented wheat beers. Statistical analysis of the results showed that for the ranges of wheat malt proportion studied, mashing‐in temperature, boiling time and fermentation temperature all had a significant influence (p <0.05) on 4VG and 4VP production. Based on the response surface plots, the optimal brewing parameters that maximized 4VG and 4VP levels were as follows: (a) wheat malt proportion 40%; (b) mashing‐in temperature 44°C; (c) boiling time 88 min; and (d) fermentation temperature 19.5°C, resulting in significantly increased levels of 4VG and 4VP (2.418 mg/L and 1.402 mg/L, respectively). These brewing and fermentation parameters were concluded to be the optimal conditions to highlight the typical flavour and aroma of top‐fermented wheat beers. Copyright © 2015 The Institute of Brewing & Distilling     

Optimisation of microwave‐assisted extraction of phenolic compounds from broccoli and its antioxidant activity

The effect of independent variables of microwave‐assisted extraction (MAE), extraction temperature (50–90 °C), microwave power (100–200 W), solvent concentration (methanol/water, 50–90%, v/v) and extraction time (1–27 min) on total phenolics and flavonoids contents as well as antioxidant activity of broccoli extracts was investigated. Response surface methodology was successfully applied for optimisation and the high correlation of the mathematical model indicated that a quadratic polynomial model could be used for optimisation of investigated responses. Considering the maximum amount of extracted total phenolics, total flavonoids and antioxidant activity expressed as ORAC value, the optimal conditions for all three investigated responses were obtained (temperature ?71.11 °C; microwave power ?167.03 W; solvent concentration ?75.95%; and extraction time 16.34 min), which is in agreement with optimal conditions obtained for each investigated responses. The development of simultaneously MAE methods for total phenolics, total flavonoids and antioxidant activity of broccoli extracts might simplify assessment of broccoli as valuables source of antioxidants.     

Optimisation of lipase-catalysed interesterification reaction for modulating rheological and heat transfer properties of frying oil

The present work reports the optimisation of enzyme interesterification reaction of rice bran oil (RBO) and refined, bleached, deodorized, palm olein (RBDPO) blend using immobilized 1,3-specific lipase, to improve the kinematic viscosity and heat transfer coefficient of oil, important for characterising heat transfer during the frying process. Four variables, namely RBO (20–80%) in RBO–RBDPO blend, reaction temperature (25–65 °C), enzyme concentration (1–13%, w/w) and reaction time (1–13 h) were selected and optimised using response surface methodology (RSM) coupled with central composite rotatable design (CCRD). The optimisation results predicted that optimum reaction conditions for preparing enzyme interesterified oil, having minimum kinematic viscosity (2.63 × 10⁻⁶ m² s⁻¹) and maximum heat transfer coefficient (262.0 Wm⁻² °C⁻¹) were at 62% RBO, temperature 65 °C, enzyme concentration 10% (w/w) and time 6.4 h. The predicted values were validated experimentally and corroborated with DSC melting profile and triacylglycerol molecular species data. This investigation could help snack food industries to develop suitable oils for frying operations.     

The preparation of an oligochitosan‐glycosylated and cross‐linked caseinate obtained by a microbial transglutaminase and its functional properties

A glycosylated and cross‐linked caseinate (GCC) with glucosamine amount of 4.74 g/kg protein was generated from caseinate and oligochitosan by a microbial transglutaminase. The applied temperature, pH and molar ratio of acyl donor/acceptor were 37 °C, 7.5 and 1:3, respectively; while caseinate concentration, transglutaminase addition and reaction time selected from single‐factor trials were 50 g/L, 10 kU/kg protein and 3 h, respectively. Electrophoretic analysis revealed the cross‐linking and glycosylation of caseinate. Compared with caseinate, GCC showed improved solubility in pH 4–11, higher digestibility in vitro and water binding capacity, about 3‐fold, but lower surface hydrophobicity and oil binding capacity (34%).