Microstructure-Extractability Relationships in the Extraction of Prepelletized Jalapeño Peppers with Supercritical Carbon Dioxide

There is a need to increase vessel loads for high‐pressure batch processes such as supercritical fluid extraction of solid substrates, but a precompacting treatment such as pelletization may negatively affect mass transfer rates. This work was aimed to quantify the effect of the microstructure of Jalapeño pepper pellets on the extraction rate and yield of oleoresins when using supercritical CO₂ at 40 °C and 320 bar as the solvent, so as to contribute with basic information that will help optimize pelletization treatments for solid substrates. Four types of substrates were obtained by considering 2 initial particle sizes and 2 initial moisture levels before pelletization, and the inner porosity and tortuosity of the resulting pellets were estimated. The internal mass transfer was favored in pellets showing a better distribution and connectedness of pores, and the extraction rate and yield improved when using pellets from flakes instead of milled flakes, with initial sample moisture exhibiting a more limited effect. A reduction in the particle size of the pellets improved mass transfer but caused a reduction in packing density, and these 2 factors had opposite effects on the “volumetric yield” of the process (mass of recovered solute per unit time and per unit volume of extraction vessel), which was also affected by prepelletizing sample conditioning.     

Carotenoid Content and Vitamin A Activity of Some Common Cultivars of Mexican Peppers (Caps&m annuum) as Determined by HPLC

Alpha-, beta, and gamma-carotenes, β-cryptoxanthin and total vitamin A activity in five different immature cultivars of peppers (Cupsicum annuum), commonly consumed in the Northwest region of Mexico, were determinated by high performance liquid chromatography (HPLC). Among the cultivars studied, “Poblano” pepper had the highest provitamin A (111.4±28.2 μg Retinol Equivalents (RE)/100g) followed by “Serrano” (86.7 ±13.0), “Jalapeño” (67.0±8.7), “Verde” (30.2±3.0), and “Caribe” (2.2 ± 0.9). In general, these values were higher than the vitamin A of peppers reported by the Mexican food composition tables and lower than the data presented in the INCAP/ICNND food composition tables for USC in Latin America.     

Flavonoids and Antioxidant Activity of Fresh Pepper (Capsicum annuum) Cultivars

Flavonoid, ascorbic acid and total phenolic content and antioxidant activity of “jalapeño” (Veracruz, Mitla, Tam Mild, Jaloro, Sweet Jalapeño), “yellow wax” [(Hungarian Yellow, Long Hot Yellow, Gold Spike (hybrid)], “Chile” (New Mexico-6, Green Chile), “ancho” (San Luis Ancho), and “serrano” (Hidalgo) peppers were investigated at green or yellow stages of maturity. Major pepper flavonoids were quercetin and luteolin which were present in conjugate forms. Total flavonoid content varied from none detectable to 800 mg/kg after hydrolysis. “Chile”, “yellow wax” and “ancho” peppers had greater flavonoid and ascorbic acid contents and antioxidant activities than “jalapeño” peppers. Sep-Pak C₁₈(tm) bound phenolic compounds, including flavonoids, correlated well with antioxidant activity (r²=0.86). Luteolin had highest antioxidant activity followed by capsaicin and quercetin on equimolar basis.     

Blanching peppers using microwaves

Enzymatic reactions are not desirable in ripe fruits and vegetables. They cause losses along transportation, storage and processing. Blanching is a pre-treatment operation whose aim is to inactivate enzymes, and is usually applied before cutting, peeling, and freezing in order to avoid browning and changes in texture. Besides inactivating enzymes such as polyphenoloxidase, peroxidase and pectinase, blanching may induce sensory and chemical changes. The purpose of this work was to evaluate changes in antioxidant activity of Capsicum annuum Jalapeño type, when treating with microwaves to inactivate polyphenoloxidase. The whole fresh peppers (85% moisture) were blended until a paste was obtained. Ten grams portions were placed in a glass container and processed in a microwave oven until the inactivation of polyphenoloxidase was reached. Inactivation of the enzyme was confirmed with a spectrophotometric method using catechol as substrate. The processed peppers samples were mixed with 80% ethanol to extract phenolic compounds that were determined by the Folin Ciocalteu method. The antioxidant activity was evaluated using the radical ABTS, as described by Charurin et al (2002). Results showed that phenolic compounds were reduced from 9.6 to 7.6 mg/ g peppers (dry weight basis) and antioxidant activity was enhanced from 29 to 42 μM de trolox/ g peppers (dry weight basis) with thermal microwave blanching. Changes in the content of phenolic compounds were confirmed using high performance liquid chromatography, and the emergence of other phenol derivatives with enhanced antioxidant activity was detected in blanched samples. It may be concluded that blanching Jalapeño peppers with microwaves may induce the formation of derivatives of phenolics with enhanced antioxidant activity.     

Physical Property Effects on Drying of Chile Peppers

Understanding effects of pepper fruit physical properties on pepper drying allows for improvement in postharvest handling and processing plus development of better cultivars. Drying tests with jalapeño peppers demonstrated that while dimensions of pepper fruits were decreasing with progressive harvests there was essentially no difference in the drying trends of peppers from the first harvest to the last. Slicing produced a similar drying trend for cultivars distinctly different in physical properties. Speed in drying peppers averaging 89.4% moisture to the 10–11% (w.b.) safe storage level was promoted by slicing as well as drying temperatures as high as 115^oC.     

Dielectric Properties of Red Pepper Powder Related to Radiofrequency and Microwave Drying

To provide useful information for drying red pepper with radiofrequency or microwave energy and designing dielectric drying equipment, dielectric properties (dielectric constant ε′ and loss factor ε?″) of red pepper powder with moisture contents ranging from 10.4 to 30.8 % wet basis were measured at different temperatures (from 25 to 85 °C) over a frequency range of 20–4,500 MHz with a vector network analyzer and an open-ended coaxial-line probe. The results showed that both ε′ and ε?″ of red pepper powder were dependent on electromagnetic wave frequency, moisture content, and temperature. The value of ε′ decreased with increases in frequency over the tested range. The ε?″ decreased with increasing frequency when the frequency was below 4,000 MHz, and increased slightly when it was above 4,000 MHz. Both ε′ and ε?″ increased as either moisture content or temperature increased, and the increases were a little greater at high moisture and temperature than those at low moisture and temperature. The moisture- and temperature-dependent permittivities of red pepper powder at several frequencies of interest could be described by quadratic models. The results of variance analysis exhibited that both moisture content and temperature had significant influence (p<0.01) on permittivities of red pepper powder. The power penetration decreased as frequency, moisture content, and temperature increased. Large penetration depth at radiofrequencies below 100 MHz could be used to dry red peppers in a large scale, while microwave energy could be used for drying red peppers in a small scale.     

OPTIMIZATION OF CHIPOTLE PEPPER SMOKING PROCESS USING RESPONSE SURFACE METHODOLOGY*

ABSTRACT

Effects of smoking time and temperature on optimal chipotle pepper production were evaluated and optimized using the response surface methodology. Batches of red jalapeño peppers were smoked under different temperatures (65.8, 70, 80, 90, 94.1C) and times (0.96, 2, 4.5, 7, 8 h). Afterward, samples were evaluated for moisture, rheological properties and total phenols. Samples were then dried from 80C to between 0.123 and 0.204 kg H₂O/kg dry matter and evaluated for rheological properties, texture, rehydration, color and phenols. Phenol content, rehydration ratio, firmness of peppers, and rheological properties and color of puree were affected (P < 0.05) by both temperature and time. Best smoking conditions used temperatures of 74–79C, and times between 8.0 and 7.4 h resulting in viscosities of 5.1–6.5 Pa·s with phenol content of 110–120 mg/kg, rehydration ratios of 3.7–4.1, firmness of 1.27–1.49 N and acceptable color. Smoking time was significantly reduced and quality maintained.

PRACTICAL APPLICATIONS

Chipotle pepper is highly appreciated by consumers because of their aroma and flavor characteristics. Chipotle pepper is obtained by smoking red jalapeño in open ovens, where combustion gases from hardwoods are passed during long times to smoke and dehydrate them. This process has the disadvantage of producing environmental contamination and wide quality variability because of a poor process control. In this study, a correlation of smoking and drying was optimized in order to determine the effect of temperature and smoking time on the physical and chemical characteristics of the chipotle pepper. Additionally, polynomial models are presented for each variable evaluated in the smoking chipotle pepper operation and optimized for the desired quality of the chipotle pepper. This information can be useful to processors because they can achieve a ninefold reduction in the smoking time compared with the traditional smoking processes without affecting the chemical and physical characteristics of chipotle peppers.     

Localization,Growth, and Inactivation of Salmonella Saintpaul on Jalapeño Peppers

Abstract: Consumption of Salmonella-contaminated jalapeño peppers has been implicated in one of the largest foodborne illness outbreaks in the summer of 2008. The objective of this study was to investigate representative groups of native microflora and the distribution, growth, and inactivation of experimentally-inoculated Salmonella Saintpaul on jalapeño peppers. Two genetically modified strains of Salm. Saintpaul producing either green- or red-fluorescent protein were constructed and used in the study. Microbiological analyses showed that jalapeño peppers contained an average of 5.6 log units of total aerobic count and 3.5, 1.8, and 1.9 log units, respectively, of enterobacteriaceae, lactic acid bacteria, and yeast/mold per gram of tissue. Strains typical of Pseudomonas accounted for 8.3% of total aerobic count, and 0.2% of which exhibited pectolytic activity. On inoculated peppers, a vast majority (>90%) of Salm. Saintpaul was recovered from stem/calyx and only a small proportion recovered from fleshy pods. Growth of Salm. Saintpaul on peppers was indicated by an increase in the population of 3 log units after incubation of samples at 20 °C for 48 h. Fluorescent Salm. Saintpaul aggregates could be readily detected on stem/calyx using stereofluorescence imaging microscopy and scanning electron microscopy. Data presented showed that Salm. Saintpaul could survive for at least 8 wk on peppers stored at 4 °C. Immersion of inoculated peppers in 200 ppm of sodium hypochlorite, acidified sodium chlorite, or peroxy acetic acid for 10 min could reduce the number of Salm. Saintpaul on stem/calyx by 1.5 to 1.7 and that on flesh by 2.1 to 2.4 log units. Practical Application: Consumption of Salmonella-contaminated jalapeño peppers has been implicated in foodborne illness outbreaks. The vast majority of Salmonella Saintpaul recovered from inoculated jalapeño peppers (>90%) was from stem/calyx. Salmonella increased by 3 log units during storage at 68 °F (20 °C) for 48 h. Salmonella could survive for at least 8 wk on peppers stored at 4 °C. Immersion of inoculated peppers in 200 ppm of sodium hypochlorite, acidified sodium chlorite, or peroxyacetic acid for 10 min reduced Salmonella on stem/calyx by 1.5 to 1.7 log units, compared with reductions of 2.1 to 2.4 log units on flesh. These results highlight the need to consider the stem/calyx as the most likely area for contamination of jalapeño peppers, and to process this commodity accordingly to minimize exposure and cross-contaminations.     

Effects of Processing Treatments on Recovery of Capsaicin in Jalapeno Peppers

Capsaicin content in frozen, cooked and canned jalapeno peppers was quantified using GLC analysis and compared to the capsaicin content in raw peper. The frozen peppers were blanched for 3 min and stored at -18°C; canned peppers were blanched for 3 min and processed at 100°C for 50 min; cooked peppers boiled at 100°C for 10 min. Results demonstrated a significant difference (a = 0.05) between each treatment and the raw pepper. Frozen and canned peppers retained approximately one-half of the capsaicinoid compounds that were present in raw pepper.     

Inactivation of Bacillus cereus Spores on Red Chili Peppers Using a Combined Treatment of Aqueous Chlorine Dioxide and Hot‐Air Drying

The effect of a combined treatment using aqueous chlorine dioxide (ClO₂) and hot‐air drying to inactivate Bacillus cereus spores on red chili peppers was evaluated. Ten washed and dried pepper samples, each comprising half of a single pepper (Capsicum annuum L.), were inoculated with B. cereus spore suspension. The inoculated samples were washed with sodium hypochlorite (NaOCl; 50, 100, or 200 μg/mL) or ClO₂ (50, 100, or 200 μg/mL) solution for 1 min and then air‐dried (25 ± 1 °C, 47 ± 1% relative humidity), which was followed by drying with hot air at 55 °C for up to 48 h. The spore populations on the samples were enumerated and their a_w and chromaticity values were measured. The spore numbers immediately after treatment with NaOCl and ClO₂ were not significantly different. A more rapid reduction in spore numbers was observed in the samples treated with ClO₂ than those treated with NaOCl during drying. A combined treatment of ClO₂ and hot‐air drying significantly reduced the spore populations to below the detection limit (1.7 log CFU/sample). B. cereus spores on chili peppers were successfully inactivated by washing with ClO₂ solution followed by hot‐air drying whereas the pepper color was maintained.     

9个品种干辣椒的品质分析及评价

为分析朝天椒、线椒和角椒3种类型干椒品质差异,对9个特色品种干辣椒（内黄新一代、花溪党武椒和丘北椒三份朝天椒,大方皱椒、沙湾线椒、陕西秦椒和甘谷线椒四份线椒,托县红辣椒和益都红辣椒两份角椒）结构特征值（籽和肉含量）和9项品质指标（粗纤维、糖、脂肪、蛋白质、水分、灰分、类胡萝卜素、辣椒碱类物质和挥发性物质）进行了检测,并通过主成分分析和聚类分析进行干辣椒综合品质评价。结果表明:籽、肉干基占比分别为21%~47%和52%~79%,主要成分为粗纤维、糖、脂肪和蛋白质,含量分别为35%~46%、11%~28%、13%~19%和14%~18%。还原糖占总糖77%~99%;含19~27种脂肪酸,不饱和脂肪酸占总脂肪酸80%以上,其中亚油酸为61%~73%;类胡萝卜素含量为73~458 mg/100 g,以辣椒红素为主（37~221 mg/100 g）;辣椒碱类物质含量18~206 mg/100 g;共检出11类挥发性物质,总含量1.12~7.65 mg/100 g。主成分分析将9项品质指标简化为3个主成分,累计方差贡献率为85.29%,反映了干辣椒品质绝大部分信息。9个品种干辣椒可聚为2类,3个品种的朝天椒为一类、4个品种线椒和2个品种角椒为一类。综合结构特征值及其与品质指标相关性分析发现:籽含量高的朝天椒脂肪、粗纤维和挥发性物质含量高,粗纤维、脂肪含量与籽含量显著正相关（P<0.05）;角椒和线椒果肉含量高,总糖含量高,且总糖与果肉含量显著正相关（P<0.05）。朝天椒是制粉和火锅底料等的优质原料,角椒适宜作制酱原料,线椒类胡萝卜素含量高,可作增色调味和色素提取等的原料,本研究结果可为9个品种干辣椒品质评价及加工辣椒品种选择提供理论参考。     

两个不同品种辣椒盐渍过程中细菌群落及品质变化研究

为探究辣椒盐渍过程细菌群落及品质变化,选取山东地区的金塔和艳红辣椒,监测了盐渍12周内样品细菌群落、可滴定酸、pH、水分含量、水分活度、氯化钠、还原糖、辣度、有机酸、核苷酸和氨基酸态氮11个指标。结果表明:两种辣椒盐渍第3周是细菌动态变化的拐点,在此之前,魏斯氏菌属、乳杆菌属等盐渍有益菌数量较多,在此之后肠杆菌属数量增加,可能由于两种辣椒的发酵程度不高,无法抑制肠杆菌的生长。两种辣椒盐渍第4周是品质与风味变化的拐点,在此之前还原糖、乳酸、乙酸、核苷酸和氨基酸态氮这些能赋予盐渍辣椒良好风味的物质含量较高,氯化钠含量适宜。因此,本研究中金塔与艳红盐渍辣椒的最适宜盐渍时间为3～4周。并且水分活度和水分含量决定了盐渍程度。金塔盐渍辣椒水分活度和水分含量分别稳定在0.80和69.3%左右,高于艳红盐渍辣椒的0.78和63.5%,因此推测金塔盐渍辣椒发酵程度更高。本研究为盐渍辣椒加工企业生产技术工艺优化提供数据与技术支持,为推进盐渍辣椒产品高质量发展提供理论支撑。     

Effect of enzyme activity and frozen storage on jalapeño pepper volatiles by selected ion flow tube-mass spectrometry

Abstract: Samples of unblanched (fresh), stannous chloride-treated, or blanched jalapeño peppers were measured for real-time generation of lipoxygenase-derived volatiles during 10 min after tissue disruption. Volatiles were also measured before and after 1.5, 2.5, 3, 6, and 9 mo of frozen storage at −15 °C. The concentration of all lipoxygenase-derived compounds was significantly higher in unblanched jalapeño peppers compared to enzyme inhibited peppers. The maximum concentration of (Z)-3-hexenal, (E)-2-hexenal, and hexanal was detected at about 1.2, 1.5, and 1.5 min after tissue disruption, respectively. A decrease in (Z)-3-hexenal and an increase in dimethyl sulfide and methylbutanal occurred in blanched compared to stannous chloride-treated peppers due to heat. Frozen storage resulted in no major changes in the lipoxygenase-derived volatiles of whole and pureed blanched peppers after 9 mo. However, in whole unblanched peppers a gradual decrease of (Z)-3-hexenal, (E)-2-hexenal, hexanal, hexenol, and hexanol was observed over time; whereas in pureed unblanched peppers these compounds increased, reached maximum concentration, and then decreased. Similarly, the minor volatiles 2-pentenal, 1-penten-3-one, (E)-2-heptenal, (E)-2-octenal, and (E)-2-nonenal showed an initial increase followed by a decline in both whole and pureed unblanched peppers. Tissue disruption increased generation and degradation rates during frozen storage. The compounds (E,Z)-2,6-nonadienal, n-propyl aldehyde, 2-isobutyl-3-methoxypyrazine, and a mixture of terpenes decreased in unblanched and blanched frozen samples, while nonanal and methylbutanal increased only in unblanched samples. Practical Application: Data obtained in this study contribute to the understanding of the dynamics of lipoxygenase-derived volatile formation upon tissue disruption of jalapeño pepper. In addition, it contributes to generate knowledge on the effect of processing techniques, namely blanching and frozen storage, on the volatile profile of these peppers. This knowledge has applications in the manufacturing, product development, and quality control areas of the food industry as useful information to help in the designing and monitoring of processes aimed to obtain products with specific aroma characteristics. For instance, maximum levels of “fresh” and “green” aroma compounds are achieved rapidly during the first few minutes after pepper tissue is disrupted. The inhibition of enzyme activity shortly after this may help to maximize concentration of these aroma notes in the product. Frozen storage produces enzymatic and chemical changes in the volatile profile of unblanched peppers. The aroma profile of blanched peppers is more stable under frozen conditions, with a lower total volatile concentration.     

Drying and rehydration behaviors of green bell peppers

In this study, the drying behaviors of green bell peppers were examined in convection dryer. The study was carried out for 3 drying temperatures (55, 65, and 75°C) and for pre-treated samples with ethyl oleate solution against control samples. The pre-treated samples dried faster than the control ones. Drying time decreased with an increase of drying temperature. Rehydration ratio of the pre-treated samples was higher than control samples. Moisture transfer from green bell peppers was described by applying the Fick’s diffusion model and the effective moisture diffusivity (D _eff ) was calculated. The D _eff values for pre-treated and control samples varied between 0.705 and 2.618×10⁻⁹ m²/sec. Activation energy values for moisture diffusion ranged from 41.67 and 52.99 kJ/mol. Drying data was fitted to 4 thin-layer drying models, namely, Lewis, Henderson and Pabis, logarithmic, and Page. The best model, which best represented the green bell peppers drying, was logarithmic.     

Employing an intelligence model and sensitivity analysis to investigate some physicochemical properties of coated bell pepper during storage

The objectives of this work were to study the effects of three different coatings (gum Tragacanth, sesame oil and gum Tragacanth–sesame oil), temperature and time on shelf life of bell pepper. Moisture reduction, shrinkage as well as firmness and colour changes were studied during 30 days at 4, 10, 15 and 23 °C. Results of this study showed that bell peppers treated with gum Tragacanth at higher temperatures, such as 10 °C, had good quality up to 30 days of storage. However, sharp changes in physicochemical characters were observed in bell peppers stored at 23 °C. In order to predict moisture reduction, shrinkage, firmness and colour changes genetic algorithm–artificial neural network model was developed. It was found that artificial neural network with eight hidden neurons truly could predict the physicochemical changes of bell pepper during storage (R² > 0.9598). The results of sensitivity analysis showed that shrinkage percentage and also changes of firmness and colour were very sensitive to storage time, while storage temperature had the most effect on moisture reduction.     

Impregnation and Infiltration Kinetics of Isotonic Solution in Whole Jalapeño Pepper Using a Vacuum Pulse

ABSTRACT: The kinetics incorporation of an isotonic solution (IS) into the whole jalapeño pepper, as a function of the vacuum pressure (p₁, vacuum application time (t₁), and relaxation time (t₂), is necessary to determining the conditions leading to the highest incorporation of IS. This study was aimed at determining the operation conditions to achieve maximum impregnation (M_in) of whole jalapeño pepper tissue, and a complete infiltration (M_in) of its inner void with an IS, using a vacuum pulse. Impregnation of whole jalapeño peppers was conducted using an IS (a_w= 0.993 ± 0.001), a vacuum pulse, and 5 levels for each process variable (t₁, t₂, p₁), according to a central composite design. The amounts of impregnated and infiltrated IS were measured by following changes in pepper weight. The p₁, t₂ had a significant effect (P < 0.01) on the rate of M_im and M_in (g IS/g pepper). It was found that the structure of whole jalapeño plays an important role in the deformation‐relaxation process, which also affects the impregnation and infiltration kinetics. A high level of p₁ (666 mbar) and t₂ (840 min) allowed to achieve the maximum values of M_im and M_in (0.07 and 0.29 g IS/g pepper, respectively). These results suggest that different driving force acts in promoting the M_im and M_in, during the t₁ and t₂. This information will be of great value in the analysis of the pickling process of whole jalapeño pepper with a hypertonic solution and a vacuum pulse.     

Supercritical CO2 Conditions Affecting Extraction of Lipid and Cholesterol from Ground Beef

Ground beef was extracted by supercritical CO₂ (SC-CO₂) with pressure ranging from 103-310 bar at 30-50°C. Higher pressure was needed to increase yield of extracted lipid. The profile of cholesterol content for the fractionated lipid extracted at 172 bar or 310 bar was generally lower in the initial stage of extraction and increased with CO₂ used. DSC thermograms indicated that, depending upon extraction conditions, the distribution of lipid components of fractionated samples either shifted toward higher melting temperatures or concentrated those lipids melting between 5-25°C.     

Improving textural quality in frozen jalapeño pepper by low temperature blanching in calcium chloride solution

The effects of low temperature blanching in calcium chloride solution of jalapeño peppers prior to freezing, on firmness retention, pH, methanol, colour and calcium ions of the product, were evaluated by response surface methodology. Texture, methanol content and pH were affected by all of the variables studied (P = 0.05). The optimum response was obtained at temperatures of 63.3–66 °C, calcium chloride concentrations of 0.17–0.21 m , immersion time of 11.6–14.4 min, with a holding time after blanching of 56.6–66.1 min. Microscopic evaluation of the thawed pepper showed that blanching in CaCl₂ solution provided a protective effect in maintaining cell wall integrity.     

Determination of microwave drying and rehydration kinetics of green peppers with the bioactive and textural properties

The aim of this study was to determine the effect of microwaves on drying and rehydration kinetics of green pepper varieties (sweet, green, and bell) and the bioactive and textural properties of dried and rehydrated peppers. Drying was performed at 90, 180, and 90 + 180 W and dried peppers were rehydrated at 25, 50, and 70°C. The best drying fits were obtained using the equations of both Sigmoid and Hii et al. for drying, and two term exponential decay was the most appropriate model for rehydration. The lowest and highest final rehydration ratio values were obtained for the peppers dried at 180 and 90 W, respectively at each temperature and pepper variety. Among peppers, bell pepper showed the lowest color change (ΔE) and it was the most potent to recover initial color in rehydration. Peppers had softer texture in both drying and rehydration treatment. Total phenolic content of peppers was reduced around 56–65% compared to the fresh pepper by drying and this decrement was reached up to 87% in rehydrated peppers. Results showed that drying at 180 W and rehydration at 70°C provided faster drying and rehydration as well maintained the quality characteristics of green peppers.