Characteristics of traditionally processed shea kernels and butter

The traditional production of shea butter requires a heat treatment of the nuts. This study compared the end products derived by two commonly used heat treatments, namely smoking and boiling followed by sun‐drying. Neither treatment influenced the moisture content of the kernels (8–10%), but the boiling treatment resulted in more free fatty acids (FFA) (6%) and a higher fat content (41%) of kernels. A sensory panel preferred shea butter from boiled kernels because of its soft texture and intense smell. This butter also had the highest values for moisture content (2%), unsaponifiable matter (7%), tocopherol compounds (125 mg g^?1), peroxide value (8 meq O₂ kg^?1), iodine value (53 mg I₂ 100 g^?1) and FFA (2%). Minor variations were noticed in the fatty acid profile. Aside from the use of butter from both boiled and smoked kernels in cosmetics, the butter from smoked kernels will be more suitable for food purposes.     

Effect of hot water treatment of in-shell pecans on physicochemical properties and consumer acceptability of roasted pecan kernels

The effect of hot water pre-treatment of in-shell pecans on physicochemical properties, consumer acceptance and purchase intent of dehulled and roasted kernels was evaluated. In-shell pecans were first subjected to hot water at 70, 80 and 90 °C for 8.6, 6.6 and 4.6 min respectively and kernels were later dry roasted at 160 °C for 10 min. The physicochemical properties of hot water treated and untreated nuts, before and after roasting were determined. Furthermore, consumer acceptance and purchase intent of the roasted kernels were determined. Hot water treatment, alone and subsequent roasting had minimal effect on pecans’ physicochemical properties. Consumers liked (P < 0.05) the colour and aroma of treated pecans. No effect (P > 0.05) of pre-treatment was observed on the acceptability of other sensory attributes. Safety claim increased treated pecans’ overall liking; however, it decreased purchase intent. Hot water treatment showed promise as a post-harvest microbial intervention strategy without affecting the physicochemical properties and consumer acceptability.     

Comparison of sensory properties of popcorn from various types and sizes of kernel

Three rice‐type popcorns (red, white and yellow) and one pearl‐type popcorn (yellow) were used in this study. All types were sized into three fractions (5 < D < 6 mm, 6 < D < 7 mm and D > 7 mm) by screening with round‐hole sieves. Samples were tested for popping quality and suitability for popping, and the sensory properties of the popcorns were evaluated. A popcorn popper with a maximum operating temperature of 226 °C was used for popping the samples (25 g). Both kernel type and size affected the expansion volume and the number of unpopped kernels. Yellow pearl‐type (YPT) and white rice‐type (WRT) popcorns showed good popping performance. The popping properties of the smallest‐sized kernels were better than those of the other fractions. Popcorn type significantly affected the flake size uniformity, flake shape uniformity, flake colour, crispness and taste of the products. Analysis of variance (ANOVA) and principal component analysis (PCA) showed that that kernel size was of great importance for the expansion volume, which was negatively correlated with number of unpopped kernels, 1000‐kernel weight and diameter ratio and positively correlated with flake size, kernels per 25 g, crispness and tenderness. © 2001 Society of Chemical Industry     

Effect of butter content and baking condition on characteristics of the gluten‐free dough and bread

This study aimed to investigate effect of butter content (0–30 g/100 g flour) and baking conditions hot air baking (HA), microwave baking (MW) and hot air‐microwave baking (HA‐MW) on quality of the rice flour dough and bread. The increased butter (up to 15 g butter/100 g flour) enhanced elastic modulus (G′) and viscous modulus (G″) of dough and specific volume of bread. Additionally, the increased butter improved crust colour and reduced hardness of the bread. The HA‐MW and MW conditions were useful for the gluten‐free bread by reducing baking time and predicted glycemic index (GI), regardless of butter content. However, enthalpy of retrogradation and crystallinity in the HA‐MW and MW bread stored at 4 °C for 7 days were increased and higher than those of the HA bread, indicating a faster staling. The predicted GI of both MW and HA‐MW bread remained at a medium level during storage.     

Enhanced inactivation of pectin methyl esterase in orange juice using modified supercritical carbon dioxide treatment

The aim of the study is to quantify the effect of ethanol addition and exposure surface on the inactivation of pectin methyl esterase (PME), a juice clarifying enzyme, in orange juice using supercritical carbon dioxide (SC‐CO₂). Addition of ethanol to the SC‐CO₂ at 2% (v/v) caused greater inactivation than SC‐CO₂ alone, with a maximum reduction of PME activity of 97% at 30 MPa and 40 °C for 60 min. As the surface area to volume ratio was increased, the rate of inactivation of PME increased. Analysis of first‐order reaction kinetic data revealed that D values were greatly influenced by ethanol addition and agitation. With the addition of 2% ethanol, the D value reduced by half, that is, 56 min from 109 min. With impeller agitation of the sample at 1100 ± 100 rpm, the D value for PME was further reduced to 43 and 30 min without and with ethanol, respectively. The activity of PME treated with SC‐CO₂ remained unchanged after 14 days of storage at 4 °C. Treatment did not significantly change pH or colour, but did significantly increase the cloud values of the juice, resulting in a cloud stabilised juice with similar qualities to fresh juice.     

Distribution of deoxynivalenol and 3‐acetyldeoxynivalenol in naturally contaminated and Fusarium culmorum infected triticale samples

Eight triticale genotypes, naturally contaminated (C) and collected from heads inoculated with two separate isolates Fusarium culmorum (I₁ and I₂) kernels were analysed for accumulation ofFusarium toxins. Triticale kernels were contaminated with deoxynivalenol (DON) and 3‐acetyldeoxynivalenol (3‐AcDON). Statistical analysis revealed significant differences between naturally contaminated samples (C) and those inoculated with isolate I₁ and I₂. The following accumulation of toxins in kernels (mean mg/kg) was found: C, I₁, I₂ – DON 0.06, 14.45, 8.09; 3‐AcDON – 0.01, 0.20, 0.49. Distribution of DON and 3‐AcDON was studied in four size fractions of kernels (> 2.8 mm; ≤ 2.8–2.5 mm, < 2.5–2.2 mm and < 2.2 mm).The highest concentration of DON and 3‐AcDON was found in the smallest fraction of damaged kernels. The percentage distribution of DON and 3‐AcDON in fraction < 2.2 mm was (C) 66%, 77%, (I₁) 38%, 27%, (I₂) 46%, 40%; and in fraction < 2.5 mm: (C) 85%, 94%, (I₁) 57%, 51%, (I₂) 80%, 76%. The naturally contaminated kernel fraction < 2.2 mm (although only 2% of all) contained 33% DON and 59% 3‐AcDON, for more toxigenic isolate I₁ 10%, 15%, 14%, less toxigenic isolate I₂ 4%, 13%, 11%, respectively, calculated on dry matter basis. No significant correlation between examined characteristics was found for either I₁ or I₂ isolate. The biosynthesis mechanism of toxic metabolites was to approximate (significantly correlated) to pair objects C/I₂.     

The effect of osmosis pretreatment on hot‐air drying and microwave drying characteristics of chili (Capsicum annuum L.) flesh

Chili flesh pretreated with or without osmotic dehydration (OD) was dried in the hot‐air drying (AD) oven at 50–80 °C or in the microwave drying (MD) oven at 60–180 W. Results showed that the samples osmotically treated in mixed solution (10% salt + 50% sucrose) had the best dehydration effect as compared with single salt or sugar solutions. During the drying process, osmotically treated samples had one falling‐rate period and their effective moisture diffusivities (D_eff) showed a rapidly linear increase with the decrease in moisture content, while directly drying samples showed a three‐phase falling‐rate period and their D_eff increased gradually at the initial period and then rapidly at the final period. When the moisture content decreased, the activation energy increased gradually; however, for AD after OD, it decreased. Among all the processes, MD at 60 W after OD presented the largest vitamin C retention rate and the best colour difference, needing less drying time.     

Influence of quinoa roasting on sensory and physicochemical properties of allergen‐free,gluten‐free cakes

The objectives of this study were to determine pasting properties of non‐roasted (NR) and roasted quinoa (RQ) and to investigate the effect of RQ on consumer acceptance and physicochemical properties of an allergen‐free, gluten‐free cake formulation. Quinoa seeds were roasted at 177 °C for 15 (R15), 30 (R30) and 45 min (R45), and flours were analysed for pasting properties. Five cakes including a commercial chocolate cake (CCC) and cakes made with NR and RQ flours were evaluated for preference by fifty panelists. Quality parameters included colour, water activity, moisture content, firmness, weight and height. Peak and final viscosity increased with roasting time. The NR cake had the highest sensory scores for appearance, colour and texture. On flavour and overall acceptability, CCC was the highest. Regarding quality data, CCC, NR and R15 cakes had similar L* values, while CCC had the lowest a*, b*, a_w, moisture content and firmness values.     

Determination of Enterococcus faecium thermal reduction in normal and high oleic peanut products

During processing, peanut butter can become contaminated with pathogenic bacteria (e.g., Salmonella). The introduction of an additional heat treatment step after roasting can help inactivate these microorganisms. In this study, trials were conducted to determine Enterococcus faecium (Salmonella surrogate) reduction rates during the roasting of high oleic (HO) peanuts and heat-treatment of normal oleic (NO) and HO peanut butters. HO peanuts were inoculated with E. faecium and roasted in a convection oven at 190°C. There was a 2 and 6 log CFU/g reduction at 300 and 480 s, respectively. D-values for HO peanut butter at 110, 120, and 125°C were 438.9, 165.1, and 80.6 s, respectively. The z-value was calculated to be 20.8°C. There was no significant difference in D-values and z-values between NO and HO peanut butter. In a pilot scale experiment, HO peanut butter was inoculated with E. faecium and agitated in a heated mixer for 21.5 min. E. faecium was reduced by 5.1 log CFU/g after 16.5 min with no apparent change in viscosity or texture. This study demonstrated that significant reductions in E. faecium can be achieved during roasting and through an additional heat-treatment step.     

Effects of storage conditions and cooking on colour and antioxidant activities of organic pigmented rice

Influences of the conditions of raw rice storage and cooking on parameters related to colour and antioxidant activities of organic hulled red fragrant rice were investigated. Raw rice samples were vacuum‐packed in oriented polypropylene/aluminium/linear low‐density polyethylene or nylon/linear low‐density polyethylene pouches and stored at ambient temperature or 15 °C up to 12 months. Cooked samples were prepared from aged raw samples. Kernel colour, total anthocyanin content (TAC) of acidic methanolic extracts as well as total phenolic content (TPC), reducing power (RP) and radical scavenging activity (RSA) of methanolic extracts and enzymatically digested samples were maintained during 12‐month storage, regardless of packaging materials and storage temperatures. Cooked kernels had larger L value, lower a and b values, and greater TAC (dry basis), comparing with the raw rice. Cooking caused drastic decrease in TPC, RP and RSA of methanolic extracts. Nevertheless, less negative impacts of cooking were found for enzymatically digested samples.     

Modeling Starch Digestograms: Computational Characteristics of Kinetic Models for in vitro Starch Digestion in Food Research

Starch digestion is mostly investigated with in vitro techniques, and time‐course measurements are common. These yield digestograms that are modeled by theoretical, semitheoretical, and empirical kinetic equations, many of which are reviewed here. The Duggleby model has Michaelis–Menten functions, and its dependent variable is on both sides of the equation with no apparent parameter for maximum digestible starch (D_∞). The Gaouar and Peleg models are equivalent. They predict both the initial digestible starch (D₀) and D_∞, and an average digestion rate, but they can reveal "biratial" digestions. The first‐order kinetic model exhibits diverse predictabilities and, when linearized, D_∞ is sometimes equated to 100 g/100 g dry starch (100%), it yields an average rate of digestion and can predict negative D₀. The log of slope (LOS) model is unique in revealing the rapid‐to‐slow digestion rate phenomenon, but without guidelines to identify such. The LOS model does not sometimes use all the digestogram data, can predict D_∞ greater than 100%, and returns zero digestion rate for some digestograms. However, some starchy materials exhibit a slow‐to‐rapid digestion rate phenomenon, as demonstrated with an example. The modified first‐order kinetic model uses all the digestogram data with practical constraints (D₀ ≥ 0 g/100 g dry starch; D_∞ ≤ 100 g/100 g dry starch), describes all digestograms, and yields an average digestion rate, but it can also be used for "biratial" digestions. In addition, the logistic and Weibull models are discussed. Using some published data, the computational characteristics of these commonly used models are presented with objective parameters to guide choices.     

Effect of extrusion on the emulsifying properties of soybean proteins and pectin mixtures modelled by response surface methodology

The objective of this study was to apply response surface methodology to estimate the emulsifying capacity and stability of mixtures containing isolated and textured soybean proteins combined with pectin and to evaluate if the extrusion process affects these interfacial properties. A simplex-centroid design was applied to the model emulsifying activity index (EAI), average droplet size (D_[4,3]) and creaming inhibition (CI%) of the mixtures. All models were significant and able to explain more than 86% of the variation. The high predictive capacity of the models was also confirmed. The mean values for EAI, D_[4,3] and CI% observed in all assays were 0.173 ± 0.015 nm, 19.2 ± 1.0 μm and 53.3 ± 2.6%, respectively. No synergism was observed between the three compounds. This result can be attributed to the low soybean protein solubility at pH 6.2 (<35%). Pectin was the most important variable for improving all responses. The emulsifying capacity of the mixture increased 41% after extrusion. Our results showed that pectin could substitute or improve the emulsifying properties of the soybean proteins and that the extrusion brings additional advantage to interfacial properties of this combination.     

Effects of Hull Scratching,Soaking, and Boiling on Antinutrients in Japanese Red Sword Bean (Canavalia gladiata)

The effects of hull processing, soaking, and boiling on the content or activity of antinutrients in the red sword bean (RSB; Canavalia gladiata) were investigated. RSB seeds were compared with kidney bean (KB; Phaseolus vulgaris) seeds that are starch based and often used as processed products in Japan. RSB seeds had higher weight, thicker hull, and higher protein content, but lower moisture content compared with KB seeds. Because of the strong and thick hull, the relative water absorption of untreated RSB seeds was very low after soaking. Seeds were soaked after dehulling, scratching, and roasting. The results showed that hull scratching was the optimal method for increasing water absorption during soaking compared with dehulling and roasting. After soaking, the water used for soaking was discarded, since it had a high content of polyphenols and bitter taste, and RSB seeds were boiled in fresh water for 20, 40, and 60 min. The results showed that polyphenol and tannin contents, antioxidant activity, and hemagglutinating activity, as well as maltase, sucrase, and trypsin inhibitor activities in scratched RSB seeds decreased significantly after boiling compared with those in raw seeds, whereas amylase inhibitor activity showed no significant change. Overall, it was concluded that the combination of hull scratching, soaking, and boiling in fresh water can reduce thermal‐stable or sensitive antinutrients in RSB and thus, significantly improve its nutritional value.     

Preparation of alcalase hydrolysed rice bran protein concentrate and its inhibitory effect on soybean lipoxygenase activity

Rice bran protein concentrate (RBPC) was prepared from defatted rice bran and hydrolysed by alcalase at different hydrolysis times. As the hydrolysis times increased, the degree of hydrolysis (DHs) increased. RBPC hydrolysate obtained at 50 min (RBPCH‐50) had the highest inhibitory efficiency on soybean lipoxygenase (LOX) activity (66%). The inhibition kinetics of the reaction analysed by Lineweaver–Burk plots indicates that RBPCH‐50 is a competitive inhibitor. RBPCH‐50 inhibited soybean LOX with an IC₅₀ of 11.73 μg μL^?1 RBPCH‐50, and the obtained K_I was 4.59 μg μL^?1 RBPCH‐50. LOX inhibitory activity of RBPCH‐50 was significantly higher than that of 50 and 100 ppm butylated hydroxyanisole (BHA) and 50, 100, and 200 ppm butylated hydroxytoluene (BHT) (P ≤ 0.05); however, LOX inhibitory activity of RBPCH‐50 was similar to that of 200 ppm BHA (P > 0.05). Therefore, RBPCH might potentially be used as a natural LOX inhibitor.     

Urinary isoflavone excretion in Korean adults: comparisons of fermented soybean paste and unfermented soy flour

BACKGROUND: This study compared the 24 h urinary excretion of isoflavone algycones after the consumption of fermented soybean paste or unfermented soy flour in a population of healthy Koreans (four males and five females). An equivalent amount (20 mg) of total isoflavone was consumed as either 52 g of soybean paste or 12.2 g of soy flour in a randomised, crossover trial consisting of two single‐time‐point feedings and having 3 day run‐in and washout periods between feedings. RESULTS: Analysis of starting materials indicated that daidzein (1.4%) and genistein (1.4%) constituted a smaller proportion of the total isoflavones in soy flour as compared with soybean paste (55.3% daidzein and 45.7% genistein). Free and glycosidic forms of isoflavones differed significantly between the two soy products. Levels of β‐glycosides as well as total glycosides (β‐glycosides, malonyl and acetyl forms) were two‐fold higher in soy flour as compared with soybean paste. Malonyl forms predominated in soy flour. CONCLUSIONS: The consumption of soybean paste resulted in significantly higher urinary excretion of both daidzein and genistein as compared with soy flour (P < 0.05 and P < 0.01 respectively). Copyright © 2007 Society of Chemical Industry     

Physicochemical properties and antioxidant activity of a synthetic cocoa butter equivalent obtained through modification of mango seed oil

This research describes the interesterification of Malaysian mango seed oil (MSO) and palm oil mid‐faction (POMF) to develop a cocoa butter equivalent. Fat blends, formulated by binary blends of palm oil mid‐fraction and mango seed oil at different ratios ({100:0}, {60:40}, {50:50}, {40:60}, {0:100}), were subjected to enzymatic interesterification. The solid fat content revealed that all interesterified blends except 100% POMF {0:100} melted completely at body temperature. The interesterified {50:50} blend exhibited a slip melting point (30.35 °C) and saponification value (186.89) close to cocoa butter (P < 0.05). Thermal behaviour analysis by differential scanning calorimetry showed fusion and crystallisation behaviour similar to cocoa butter. Moreover, both the blend and cocoa butter scavenging abilities were based on the 2,2‐diphenyl‐1‐picrylhydrazyl assay, with the concentration required to reduce radical absorbance by 50% (IC₅₀) of 43.08% and 41.1%, respectively. Therefore, the MSO: POMF blend may have use as a health‐promoting food in human diets.     

Effect of thermosonication in a batch system on the survival of spore‐forming bacteria

Thermosonication may help reduce bacteria counts responsible for spoilage in dairy products. Vegetative cells and spores of Geobacillus stearothermophilus, Anoxybacillus flavithermus and Bacillus subtilis (spores only) were treated with either heat alone or thermosonication in a batch system from 0 to 120 s in tryptic soy broth and 2% fat milk at 72 and 73 °C. D‐values for vegetative cells were calculated and were reduced after thermosonication. Maximum reduction in vegetative cells after thermosonication was 1 log after 30–45 s and for spores was ≤0.2 log after 120 s, which may not influence dairy product quality in scale‐up systems.     

Structures and Functional Properties of Starch From Seeds of Three Soybean (Glycine max (L.) Merr.) Varieties*

Structures and functional properties of starch from high‐protein, lipoxygenase‐free and low‐linolenic acid soybean variety seeds collected 20 d prior to harvest were investigated. Soybean starches exhibit C_B‐type X‐ray diffraction patterns, and granule diameters were very small (0.7 to 4 µm). Soybeans, 20 d prior to harvest contained 10.9–11.7% starch (dry basis). Apparent amylose content was 19–22% and absolute amylose content was 11.8–16.2%. Amylopectin weight‐average molar mass ranged from 5.1 to 11.3×10⁸ g/mol. Amylopectin average branch chain‐length, determined by anion‐exchange chromatography with an amyloglucosidase post‐column and pulsed amperometric detector, was very short relative to other starches (20.4–20.9). Onset gelatinization temperature ranged from 52–54°C, and ΔH was 12–13 J/g. Paste viscosity was low relative to other starches, especially peak (81–93 RVU) and final (93–106 RVU) viscosity. The apparent amylose content of the low‐linolenic acid soybean starch was significantly higher than that of high‐protein soybean starch, and absolute amylose content of low‐linolenic acid soybean starch was significantly higher than that of lipoxygenase‐free soybean starch. Based on our results, investigations on whether soybeans with different fatty acid oil composition have different starch structures would be worthwhile. Field replicates for each soybean variety exhibited high variation in starch characteristics, with further differences in starch structures and functional properties likely to be determined once variation is minimized.     

Thermal Inactivation Kinetics of Tulane Virus in Cell‐Culture Medium and Spinach

Human noroviruses (HNoVs) cause significant gastrointestinal disease outbreaks worldwide. Tulane virus (TV) is a cultivable HNoV surrogate widely used to determine control measures against HNoVs. The objective of this study was to determine the heat inactivation kinetics (D‐ and z‐values) of TV in cell‐culture media and on spiked homogenized spinach using the first‐order and Weibull models. TV in cell‐culture media at approximately 7 log PFU/mL (PFU—plaque forming unit) in 2‐mL glass vials was heated at 52, 54, and 56 °C for up to 10 min in a circulating water bath. Survivors were enumerated using confluent host LLC‐MK2 cells in six‐well plates by plaque assay. Data from three replicate treatments assayed in duplicate were analyzed statistically. D‐values by the first‐order model for TV in cell‐culture media at 52, 54, and 56 °C were 4.59 ± 0.05, 2.91 ± 0.05, and 1.74 ± 0.07 min, respectively, with a z‐value of 9.09 ± 0.01 °C (R² = 0.997). The Weibull model showed t_d = 1 values of 2.53 ± 0.08, 1.99 ± 0.10, and 0.57 ± 0.64 min, respectively, at the same temperatures. The D‐values for TV in spinach were 7.94 ± 0.21, 4.09 ± 0.04, and 1.43 ± 0.02 min and the z‐value was 10.74 ± 0.01 °C (R² = 0.98) by the first‐order model and 4.89 ± 0.02, 3.21 ± 0.45, and 0.25 ± 0.38 min for the Weibull model at 50, 54, and 58 °C, respectively. In comparison to previously reported results for the cultivable HNoV surrogate, murine norovirus ‐1, TV in cell‐culture media and spiked on spinach homogenates showed lower D‐ and z‐values. TV may not be an ideal HNoV surrogate for heat inactivation studies in cell‐culture media or homogenized spinach in vacuum bags.