Kinetics of conductive hydro-drying of pumpkin (Cucurbita moschata) pulp

Pumpkin (Cucurbita moschata) samples were dehydrated by conductive hydro-drying (CHD) (1 atm, 80 °C), sliced and purées, both structures with thicknesses of 1.5, 3 and 6 mm. Drying kinetics were analyzed and the effective diffusivity (D ef) was determined in both structures at the three thicknesses. Drying curves were fitted to ten kinetic models: Lewis, Henderson & Pabis, Logarithmic, Page, Wang & Singh, Page Modified, Midilli, Diffusion Approximation, Two-term Exponential and Verma. D ef was determined by analytical solution of Fick's Second Law in rectangular coordinates by Crank's method. In general, the semi-empirical model that best fit showed was Midilli's model. However, the importance of phenomenological models such as the analytical solution of Fick's second law for process scaling and equipment design should be considered. These modeling results aid in predicting performance and fine-tuning hydrodrying processes for sustainable, high-quality food. Future applications may involve integrating these models into industrial-scale hydrodryers, reducing energy consumption and environmental impact.

"Optimization and evaluation of quality characteristics of traditional Indian snack (baked balls) made by using pumpkin peel powder"

The baked balls (traditional Indian snack litti) were formulated along with the standardization and optimization of different ingredients and recipe. The optimization was done by using response surface methodology. Box behnken model was selected for the optimization in which wheat flour (40-80%), roasted bengal gram flour (10-50%), and pumpkin peel powder (2.5-15%) were selected as an independent factor for the standardization of baked balls recipe against the dependent factors including sensory attributes (colour and texture), moisture content and water activity. The proximate analysis of optimized baked balls resulted in energy, carbohydrate, protein, fat, dietary fibre, calcium, iron, and zinc value as 310 kcal, 55.6 g/100 g, 13.78 g/100 g, 2.73 g/100 g, 40.18 mg/100 g, 4.57 mg/100 g and 2.97 mg/100 g respectively. Additionally, carotenoid content of control and optimized baked balls was found to be 284 µg/100 g and 838.93 µg/100 g whereas the ascorbic acid content was observed as 1.84 mg/100 g and 5.82 mg/100 g respectively. It showed a significant increase in nutritional parameters when compared with control (wheat flour) baked balls. This study also evidenced that pumpkin peel powder can be used as a food supplement for various nutritional components.

Effect of pretreatments and solar tunnel dryer zones on functional properties, proximate composition, and bioactive components of pumpkin (Cucurbita maxima) pulp powder

Pumpkin fruits are large in size and need to be cut into pieces for use. The quality and storage life of cuts rapidly deteriorated. Big size fruits can be converted to shelf stable product to minimize postharvest loss using solar driers. However, drying temperature and RH in long solar tunnel drier not uniform and may affects quality of dried products. Therefore this research work aimed to investigate the effects of pre-drying treatments and solar tunnel dryer zones on the functional properties, proximate composition, and bioactive components of pumpkin pulp powder. Three groups of pumpkin slices were pre-treated in 1% citric acid (20 min), 2% salt (20 min) solutions, and the other group blanched at 65 °C in 1% salt solution (2 min), untreated sample used as a control. Pre-treated samples then dried in three zones of tunnel solar drier (zone I, zone II and zone III). Treatment combinations were laid down in factorial RCBD replicated 3 times. Results showed that pulp powder from salt pre-treated slice and dried at zone III results in the highest values of shrinkage, rehydration ratio, water holding capacity, and bulk density. Moisture content decreased from zone I to III, and with salt blanching in range of 8.2 to 6.4%, no effect in crude fat content, slices pre-treated in 2% salt solution results is better crude protein and fiber contents in zones. Better retention of total polyphones, beta-carotene, ascorbic acid, with high DPPH scavenging activity and lowest IC₅₀ values were observed for salt pre-treated sample but dried in zone II of the drier. In general relatively better functional properties, proximate composition and bioactive compounds of the powder can be preserved when slices pre-treated in 2% salt solution and dried in zone II of solar tunnel drier characterized by 54.9 ± 3.7 °C, RH value of 31.4 ± 3.4% and air velocity of 0.45 m/s.

Effect of Pretreatments and Solar Tunnel Dryer Zone on Drying Characteristics and Stability of Pumpkin (Cucurbita maxima) Slices

Drying fruits and vegetables can be achieved using different drying methods based on the crop's economic value and the technology's affordability. However, in Sub-Saharan Africa, where sunlight intensity and duration are high, it is recommended to use solar drying methods. A solar tunnel dryer is one of the methods commonly used to produce dried fruits and vegetables. It is necessary to determine the drying kinetics at different dryer zones and select a suitable drying kinetics model to overcome the limitation. In addition, pretreatment methods are commonly recommended to improve the quality of the dried product. This work aimed to determine the drying kinetics of pumpkin slices at different zones of drier and pretreatment effect on product quality. Three zones of drier and four pretreatments were employed in the two-factor factorial experiment. Seven thin layer kinetic models were evaluated. pH, TSS, TA, moisture content (MC), and water activity (a_w) were determined for quality evaluation. Recorded data showed that the temperature in the tunnel increased from zone I to III with a decrease in RH. Results showed a higher drying constant (K) and effective diffusivity (D_eff); drier zone III > II > I. Pretreatments also showed a significant effect on K and D_eff. Regardless of pretreatment types, two-term exponential and diffusion models are better fitted for zones I and II/III, respectively. With pretreatments and drier zones, the TSS value increases from zones I to III but with a decrease in titratable acidity, moisture content, and water activity. From the result, it can be concluded that different drying rates are observed in different zones. However, a better quality of pumpkin powder was observed in drier zone II for pumpkin slices pretreated with a 2% salt solution. It is recommended to create a drying medium that resembles zone II or better to use the recommended kinetic models to predict the drying time for each zone for a better quality product by avoiding under- or over-drying of slices.

Nutritional Value, Phytochemical Potential, and Therapeutic Benefits of Pumpkin (Cucurbita sp.)

Pumpkin is a well-known multifunctional ingredient in the diet, full of nutrients, and has opened new vistas for scientists during the past years. The fruit of pumpkin including the flesh, seed, and peel are a rich source of primary and secondary metabolites, including proteins, carbohydrates, monounsaturated fatty acids, polyunsaturated fatty acids, carotenoids, tocopherols, tryptophan, delta-7-sterols, and many other phytochemicals. This climber is traditionally used in many countries, such as Austria, Hungary, Mexico, Slovenia, China, Spain, and several Asian and African countries as a functional food and provides health promising properties. Other benefits of pumpkin, such as improving spermatogenesis, wound healing, antimicrobial, anti-inflammatory, antioxidative, anti-ulcerative properties, and treatment of benign prostatic hyperplasia have also been confirmed by researchers. For better drug delivery, nanoemulsions and niosomes made from pumpkin seeds have also been reported as a health promising tool, but further research is still required in this field. This review mainly focuses on compiling and summarizing the most relevant literature to highlight the nutritional value, phytochemical potential, and therapeutic benefits of pumpkin.

An improved protocol for natural convective drying of pumpkin

The most effective way to preserve agricultural product is drying. However, vegetable drying is an energy-consuming procedure. Convective drying is the mode considered in this work. The study intends to explore a new way of pumpkin drying, which reduces drying time and minimizes heat consumption. The study considers pumpkin thin slices and pumpkin samples with cubic shape. The samples were subjected to free convection airflow at different temperatures (40 °C, 46 °C, 52 °C, and 60 °C) for each run. A varying airflow temperature was also considered. Airflow velocity was generated by buoyancy forces for each temperature. Drying curves were plotted and fitted to the widely used thin-layer drying models. The modified Page model came out as the best-fitted model. The effective diffusivity coefficient was determined for each case using the slope moisture curve. It appeared that diffusivity was high and drying time was short, for high temperature. Drying processes for slice configuration and cube configuration showed that the latter was more efficient. When applying the regime of increasing temperatures to the cubic samples, data analysis showed that effective diffusivity was higher during the third step in comparison to all the other drying temperatures and the total drying time was similar to that obtained at drying regime on high temperature. With this procedure, the final consumed energy was much less and the time was shorter.

Quality of New Functional Powdered Beverages Enriched with Lyophilized Fruits—Potentially Bioaccessible Antioxidant Properties, Nutritional Value, and Consumer Analysis

This study evaluates nutrients and health-promoting compounds responsible for antioxidant capacity in eight novel formulations based on lyophilized fruit and vegetable powders. The composition contained lyophilized carrot, pumpkin, lentil sprouts, raspberry, strawberry, and apple. The effect of functional additives on the antioxidant, nutritional, and functional characteristics of powdered beverages was determined in the powders and after rehydration followed by in vitro digestion. The antioxidant activity, phenols, vitamin C, and reducing power were significantly higher in the powders enriched with additives having potential functional properties. Furthermore, the analyses indicated that all the powdered formulations may be potential sources of total starch (100–112 mg/100 mL) and proteins (125–139 mg/100 mL). The designed powdered beverages after reconstitution exhibited high antioxidant content, reasonable consumer acceptance, and good in vitro bioaccessibility. The best results of antioxidant capacity were obtained for beverages enriched with raspberry, i.e., 10.4 mg Trolox equivalent (TE)/100 mL and 12.1 mg TE/100 mL rehydrated at 20 °C and 80 °C, respectively. Additionally, color characteristics were used as indicators of the quality of the powdered beverages. This research promotes the reduction of food waste, since whole plant tissues are used, thus allowing maximum exploitation of food raw materials; moreover, drying provides stable shelf life.

Functional and nutraceutical properties of pumpkin – a review

Purpose

The purpose of this paper is to review the nutritional and food value of pumpkin Cucurbita, along with different health benefits. Cucurbita (pumpkin) is an herbaceous vine, member of Cucurbitaceae family. It is an edible, heat-sensitive plant, which has an abundant amount of active compounds such as carotenoids, alkaloids, flavonoids, polyphenols, tannins, tocopherols, phytosterols and cucurbitacin, accounted for numerous health benefits, namely, antidiabetic, antioxidant, anticarcinogenic, hypotensive, hyper protective activities.

Design/methodology/approach

Major well-known bibliometric information sources such as Web of Science, Scopus, Mendeley and Google Scholar were searched with keywords such as nutrition value of Cucurbita, Cucurbita utilization, bioactive compounds of pumpkin, health benefits, processing, food formulations and current scenarios were chosen to obtain a large range of papers to be analyzed. A final inventory of 105 scientific sources was made after sorting and classifying them according to different criteria based on topic, academic field, country of origin and year of publication.

Findings

The comprehensive review of different literature, data sources and research papers seeks to find and discuss various nutritional benefits of pumpkin. It contains all necessary macro- and micro-nutrients, amino acids, vitamins, antioxidants and bioactive compounds with a relatively low amount of antinutrients. The recent upsurge in consumer interest for health-promoting products has opened up new vistas for plant products containing bioactive compounds in different food formulations.

Originality/value

This paper contains information regarding the chemical composition, nutritive value, phytochemical studies, pharmacological properties, bio-accessibility, food and industrial applications of pumpkin. Worldwide, pumpkin is used as food additive in various food products such as candy, weaning mix, corn grits, kheer, jam, crackers, bread, etc. Effect of different processing methods such as high temperature, pH, blanching, oven drying, freeze-drying to retain or minimize its losses in case of color, texture, flavor, and the carotenoids are of concern. The review paper highlights the nutritional, therapeutic, potential and processing attributes.

Effect of Drying Methods on the Rheological Properties of Sugar Beet Pulp Pectin

The effect of drying methods on the rheological properties (apparent viscosity, storage (G′) and loss (G″) moduli, creep behavior) of sugar beet pulp pectin (SBPP) was investigated using steady shear, frequency sweep, activation energy and creep-recovery tests. SBPP was extracted from sugar beet and dried using freeze (FD), hot air (HD), vacuum (VD) and spray (SD) drying methods. The HD sample showed highest apparent viscosity and the VD sample had the highest activation energy. The 1 % (w/v) samples had higher activation energy than 2 % (w/v) samples. The G′ and G″ versus angular frequency data followed the Power Law model reasonably well (R2 > 0.915). The FD sample deformed the most during the creep test.