Freeze-dried Potato Research Articles

Water uptake by freeze-dried potato and soybean powders: experiments and simulations

Water uptake by freeze-dried potato and soybean powders: experiments and simulations

A Novel Approach to Improving the Rehydration of Freeze-Dried Potatoes through Electrical Treatment

A Novel Approach to Improving the Rehydration of Freeze-Dried Potatoes through Electrical Treatment

Влияние сублимационной сушки на качественные показатели клубней картофеля

Freeze-dried vegetable production is intensively developing due to its advantages - a four-time decrease in the weight of supplied freeze-dried potatoes, increased shelf life by dozens of times, and the resistance of freeze-dried products to temperature fluctuations. To study the quality indicators of potato tubers before freeze-drying and after it using standard techniques, the authors analyzed domestic and foreign varieties including those with pigmented flesh and peel. Freeze-drying of potato tubers was carried out in the vacuum-sublimation machine USS‑5 in two stages: rapid freezing of 2 to 3 cm thick sample plates to -30°C during 4 h and heating to +50°C during 2.5 h. Raw potato tubers and freeze-dried samples were tested for antioxidant, phenolic and flavonoid content using standard methods. The results of biochemical analysis showed the total content of alcoholsoluble flavonoids in fresh potato pulp in recalculation on quercetin 0.08 to 1.13 mg/g raw weight, in freeze-dried samples - 0.22 to 1.46 mg/g dry weight; total content of low-molecular antioxidants in fresh pulp from 0.12 to 1.92 mg/g raw weight, phenolic compounds in freeze-dried samples from 0.55 to 4.63 mg/g dry weight in gallic acid equivalents. The study also focused on the determination of the moisture absorption level of freeze-dried potato tuber slices. Moisture saturation of freeze-dried potato slices when immersed in room temperature water occurred within 60 min. Freeze drying had no effect on the antioxidant content of the potato tubers. Therefore, this method can be used to produce healthy foods.

The influence of freeze drying on the quality indicators of potato tubers

In Russia, there is an active development of the Arctic, the Northern regions, the supply of which with food is difficult. The production and supply of freeze-dried vegetables and potatoes is an important task, given that the need for potatoes in terms of nutritional standards is higher than all other vegetables combined, and cargo deliveries are by weight, reducing the weight of the supplied potatoes by four times, taking into account the increase in shelf life by dozens of times and resistance of the freeze-dried product to frost, this is an extremely important area of research. The purpose of the research is to study the quality indicators before and after freeze-drying of potato tubers of domestic and foreign varieties, including varieties with pigmented pulp and skin. The measurements were carried out in the laboratory of the A.G. Lorch” using standard techniques. According to the results of biochemical analysis, the total content of alcohol-soluble flavonoids in terms of quercetin in tubers was 0.08-1.13 mg/g in wet weight, in freeze-dried samples - 0.22-1.46 mg/g in dry weight. The content of low molecular weight antioxidants in fresh potato pulp varied from 0.12 to 1.92 mg/g wet weight, the total content of phenolic compounds in sublimated samples varied from 0.55 to 4.63 mg/g dry weight in gallic acid equivalents. A significant advantage of this drying is the ability to restore freeze-dried potatoes in 60 minutes. The conducted studies confirm that the content of antioxidants in different varieties of potatoes is different and remains after freeze-drying, which makes it possible to select potato varieties for creating healthy food products. Freeze drying of vegetables is an energy-intensive operation. However, according to domestic and foreign manufacturers of freeze-dried products on an industrial scale, the high quality of finished products, the absence of costs for creating a special temperature and humidity storage regime, and a low specific gravity offset the costs of drying.

Biomass-based Janus three-dimensional water evaporator for highly effective desalination and wastewater purification

An efficient Janus three-dimensional (3D) water evaporator with low-cost and energy-saving was developed for desalination and wastewater purification. The bottom layer of this water evaporator is composed of freeze-dried potato, which has an intricate 3D porous structure that can efficiently transport water through the capillary effect. Additionally, the freeze-dried potato also has the function of heat insulation, which can reduce heat loss and improve the light-to-heat conversion efficiency (η). The upper layer of the water evaporator is made of manganese-doped cobalt sulfide (Mn-CoSx) and agar hydrogel. The primary function of Mn-CoSx is to capture sunlight, which has full-spectrum absorption properties in the 200–2500 nm range. The role of agar hydrogel includes immobilizing Mn-CoSx, linking with freeze-dried potato, and transporting water molecules. Under one-sun irradiation, the water evaporator has a higher evaporation rate (1.75 kg m−2h−1) and η value (110.2%).

Enhancing bioaccessibility of resveratrol by loading in natural porous starch microparticles

Resveratrol (RSV) is a lipophilic polyphenol susceptible to photo- and thermal degradation, and strategies are to be studied to enable its distribution in food matrices, prevent its degradation during storage, and increase its bioaccessibility during digestion. In this study, the porous matrix of natural starch, in the form of milled freeze-dried potato microparticles (FDPMs), was studied as an absorbent to load RSV. The binary solvent of ethanol and polyethylene glycol 400 (40:60 v/v) was used to dissolve 30% w/v RSV for diffusion into FDPMs. After ethanol was evaporated, the loading capacity was 112 mg RSV/g FDPMs and was maintained at 104 mg RSV/g FDPMs (92.9% retention) after 110-day ambient storage. The RSV stability under UV irradiation at 253 nm was improved by 32% due to shielding effect of FDPMs, and the ferric reducing power was 25% higher than the pristine RSV. The release of RSV in FDPMs was significantly higher than pristine RSV during simulated gastric and intestinal digestions (82.3% vs 51.4% bioaccessibility). The increased reducing power and bioaccessibility were supported by the amorphous state of RSV in FDPMs. The present study illustrates the potential of porous vegetable microparticles as natural matrices to load lipophilic bioactive compounds in functional foods.

Characterization of gluten-free rice bread prepared using a combination of potato tuber and ramie leaf enzymes.

A combination of freeze-dried powder of disproportionating enzyme (D-enzyme)-containing potato tuber and β-amylase-containing ramie leaf was used to improve the gluten-free (GF) bread, and its physicochemical properties were characterized. The presence of D-enzyme and β amylase in the potato tuber and ramie leaf was confirmed. Sixty five percent of partially gelatinized rice flour and 20% corn starch was combined with 10% freeze-dried potato tuber and 1% ramie leaf powder, and baked. The specific volume increased by 23% compared to the control with improved internal characteristics. Texture profile analysis revealed that retrogradation of the bread was retarded when stored for 90h at 4°C. The bread crumb amylose content was reduced from 14 to 9% and amylopectin branch chain-length distribution was rearranged, whereby the proportions of the branch chains with Degree of polymerization (DP) < 9 and DP > 19 decreased. The results suggest that D-enzyme and β-amylase cooperatively altered amylose/amylopectin ratio and amylopectin structure.

Differentiating Chuño blanco and Chuño negro in archaeological samples based on starch metrics and morphological attributes

Identification of diagnostic signatures of food processing practices in the starch grain record has recently revolutionized our ability to understand foodways, particularly in the Old World. In this paper, we build upon extant starch grain research on chuño, a freeze-dried potato product produced in the Andean highlands, to develop criteria for the identification of chuño types in the archaeological record. We analyzed two hundred modern starches from four chuño blanco and chuño negro sources in Peru and Bolivia. Our results reveal differences in morphology and statistically significant (p < 0.0001) discrepancies in size metrics between the two chuño types that can be used to distinguish archaeological starches. This set of criteria has great potential to inform our understandings of the origins of potato domestication, the development and spread of detoxification methods, taste preferences and cuisine, social (ayllu) affiliations, and highland to lowland trade networks in the Andean past.

Unfrozen state by the supercooling of chuño for traditional agriculture in altiplano andes

Abstract The freezing point and supercooling process are discussed for their impact on the traditional Andean freeze-dried potatoes called chuno. The freezing point depends on potato species, but typically it is slightly below zero to −3 ​°C; supercooling always occurs before the potatoes freeze, and the lowest supercooling point (LSP) can reach −4.3 ​°C. Recently many of the potato fields near Lake Titicaca are not cold enough to freeze tubers for chuno, and the loss of this food source will be critical in the future.

Effects of temperature and shear on the structural, thermal and pasting properties of different potato flour

BackgroundThe properties of potato flour will be different due to different processing parameters, which will affect their processing adaptability. In this paper, different potato flour were investigated to determine viscoelastic properties and structural transformation using thermodynamics, rheological and spectrum methods. Potato flour was prepared by drying at different temperature after soaking in citric acid, microwave and steamed respectively. The treated samples were dried by hot air and then compared with the freeze-dried potato flour. Four kinds of potato flour showed different properties after shearing at high temperature.ResultsDifferential scanning calorimetry (DSC) results revealed that potato flour with low gelatinization had lower enthalpy and faster melting process than freeze-dried potato powder. RVA and texture results showed that potato flour with low gelatinization had the best retrogradation property and the stable gel. X-ray diffraction (XRD) patterns revealed that the crystalline properties of different potato flour after shearing at high temperature were the same. In addition, low gelatinization potato flour presented a crystalline structure or strong internal order. Fourier-transform infrared spectroscopy (FTIR) spectra showed that high temperature and shearing mainly caused δ-deformation of O–H in intact potato granules.ConclusionFreeze drying and hot air drying at low temperature made potato flour had better gel stability than microwave and steamed treatment. Hot air drying at low temperature made potato flour had good retrogradation after hot shearing, which was more conducive to the formation of hot-processed products.

Reimagining Bolivian cuisine: Haute traditional food and its discontents

This article considers the emerging Bolivian gastronomic discourse as a project fraught with tensions. On the one hand, the discourse surrounding Bolivian cuisine, as presented in urban restaurants, highlights a new kind of nationalism that promotes regional cooking and innovation. This process has elevated indigenous ingredients, such as quinoa, chuño (freeze-dried potatoes), and llama meat, to the status of delicacies. This gastronomic emergence parallels the recent rise of an indigenous middle-class, as well as the shifting political boundaries between indigenous and non-indigenous in the era of President Evo Morales. Nevertheless, elite urban forms of Bolivian cuisine only partially transcend gender, class, and ethnic divides; they sometimes have the (unintended) effect of highlighting and re-inscribing existing social fault-lines. This article considers how indigenous Bolivian women are used to mark Bolivian cuisine, while they are simultaneously marginalized from it. While indigenous women dominate the “culinary field” of quotidian eating in domestic and marketplace arenas, they are far less evident in the “gastronomic fields” of elite restaurants, cookbooks, and written texts. Despite this exclusion, their presence is often invoked through ethnically-marked clothing such as the pollera and their symbolic production of “local” food.

State/phase transitions induced by ice recrystallization and its influence on the mechanical properties of potatoes (Solanum tuberosum L.) var. Russet Brown

Thermal transitions in frozen foods may occur due to temperature fluctuations during storage and distribution, inducing ice recrystallization and loss of food quality. This study evaluated the effects of state/phase transitions on ice recrystallization and on mechanical properties of unblanched and blanched potatoes. Potato samples were frozen at −32 °C for 5 days to achieve a glassy state and then subjected to temperature fluctuations of varying amplitudes to achieve different physical states: glassy state with temperature fluctuation, rubbery and thawed states. Ice crystal size of potatoes was evaluated using scanning electron microscopy (SEM) through pore analysis of freeze-dried potatoes. Hardness of potatoes was determined using texture analyzer. Temperature fluctuation increased the ice crystal size and reduced the hardness of potatoes-the changes depended on the severity of temperature fluctuations and the treatment medium. Findings may inform improved packaging design, storage and transportation strategies to minimize quality changes in frozen potatoes.

Physical characteristics and nutritional composition of gluten-free bread with share of freeze-dried red potatoes

ABSTRACTThe aim of the study was to compare nutritional composition and physical properties of gluten-free bread samples with a 5% addition of freeze-dried red potatoes (variety: Blue Star, Magenta Love, Violeta), in order to check the suitability for nutritional enrichment of such products. It was observed that the use of potato variety Magenta Love resulted in the most beneficial nutritional quality of gluten-free bread (especially high content of insoluble fibre), and its best physical properties (high volume, low hardness, good cohesiveness), which were reflected in the highest consumer acceptance of this product. The use of freeze-dried red potatoes could be recommended as an innovative way to enrich gluten-free products in nutrients and improve their technological quality.

Gluten-free bread with an addition of freeze-dried red and purple potatoes as a source of phenolic compounds in gluten-free diet

The basis for gluten-free diet is often gluten-free bread, which is usually characterized by a low-nutritional value, and lacks any pro-health properties. Only after an introduction of gluten-free raw materials, containing high level of bioactive compounds it would be possible to obtain the product with a pro-health potential. The aim of the study was to analyze the content of bioactive compounds (total phenolic content, phenolic acids, flavonoids, flavonols, anthocyanins and carotenoids) in gluten-free bread prepared with 5% addition of freeze-dried red and purple potatoes as well as to assess their antioxidant potential. Summarizing, among the analyzed gluten-free breads with an addition of freeze-dried red and purple potatoes, the best results could be obtained by using variety Magenta Love (red potato), which provided the highest levels of phenolic compounds and carotenoids and also antioxidant and antiradical activity.

Texture and color analysis of freeze-dried potato (cv. Spunta) using instrumental and image analysis techniques

ABSTRACTMost typical approaches for measuring color and texture properties are time consuming. An image-based method was used to evaluate the texture and color in freeze-dried potatoes. Microstructure of cooked, cooked freeze-dried and rehydrated potatoes were analyzed by scanning electron microscopy. Texture properties were analyzed by a texture analyzer and image analysis. Color was determined with a spectrocolorimeter and a digital camera. Significant differences (p < 0.05) were obtained for cooked and cooked freeze-dried rehydrated potatoes. A linear trend was applied for instrumental and image features for texture and color values. Results showed that texture features of images, such as contrast, entropy, energy, and homogeneity (calculated from grey level co-occurrence matrix), showed correlations with instrumental texture features, such as hardness, adhesiveness, chewiness, cohesiveness, and resilience. Similar results were also obtained for color features. This study showed that image processing techniques could be applied as a useful tool to analyze quality in potatoes.

Electrochemical Impedance Spectroscopy as an Alternative to Determine Dielectric Constant of Potatoes at Various Moisture Contents

The dielectric (DE) properties, specifically the DE constant (ε') and loss factor (ε''), were measured for vacuum-dried and freeze-dried potato samples at a microwave frequency of 2.45 GHz over a range of different moisture contents (MCs) using a DE probe and also a 2-probe electrochemical impedance spectroscopy (EIS). Third-order polynomial models (ε' = f₁(MC); and ε'' = f₂(MC)) at room temperature were developed for regression analysis. Additionally, at various temperatures (T), biphasic 3rd-order polynomial models (ε' = f₁(MC, T); and ε'' = f₂(MC, T)) were obtained to determine ε' and ε'' as a function of MC and T using measured data. The vacuum-dried potato sample showed a good fitness of ε' and ε'' (R² = 0.95 and 0.96, respectively) to the regression model with the range of MCs from 18% to 80% (w/w), while the freeze-dried potato sample showed a good fitness of ε' and ε'' to the 1st-phase regression model with MC < 50% w/w (R² = 0.95 and 0.96, respectively) and the 2nd-phase regression model with MC > 50% w/w (R² = 0.94 to 0.96). EIS measurements were also used to obtain correlation impedances for ε' and ε'' determined by the DE probe method. The resulted regression analysis meets the demands for simple, rapid, and accurate assessment for transient values of ε' and ε'' of food products during dehydration/drying processes. The EIS method was verified to be a successful alternative to direct measurements of ε' and ε''.

Browning prevention in rehydrated freeze-dried non-blanched potato slices by electrical treatment

Freeze-drying (lyophilization) has many advantages. The color of the freeze-dried product resembles that of the fresh tissue, in contrast to the frequently darker color resulting from conventional oven-drying. However, freeze-dried non-blanched potato slices suffer from considerable browning following rehydration. Electrical treatment of the fresh tissue (40 V/cm for 1 min) without heating and before lyophilization reduced its browning after rehydration: L* values (lightness) of the untreated and electrically treated rehydrated tissues were 50.4 ± 0.3 and 84.3 ± 0.8, respectively. Image processing revealed that the porosity of the freeze-dried potato is not significantly influenced by the prior electrical treatment. Compression of any of the treated freeze-dried specimens always yielded characteristic sigmoid stress–strain curves. The freeze-dried blanched potato specimen was tougher than both the freeze-dried fresh potato and its electrically treated counterparts.

Influence of Structure on Saltiness and Sweetness of Dehydrated Food Products

Pore structure of foods influences the quality and texture of dehydrated food products. The development of food products with different pore structures and its effect on the sensory characteristics of the products were investigated. Potatoes and bananas were osmotically pre-treated using salt and sucrose solutions, respectively, and dehydrated with various drying methods, such as air drying, freeze drying, and vacuum drying, in order to obtain different pore structures. Simple mathematical models were developed in order to correlate the structural properties with process conditions. Depending on the drying method, porosity varied from 5% to 75% for potatoes and from 15% to 60% for bananas. Porosity was higher for the samples that were freeze-dried at lower pressures, followed by samples freeze-dried at higher pressures and, finally, vacuum- and air-dried samples. The surface areas of the dried samples varied between 0.961 and 3.040 m2/g, which are typical values for dehydrated foods. Freeze-dried potatoes and bananas were found to be saltier and sweeter (Score 6.5–7.8), respectively, than air- and vacuum-dried products (Score 4.8–5.8). Bananas and potatoes with the highest porosity and the highest specific surface areas presented more intense taste, providing the opportunity of reducing the levels of salt and sugar of the produced products without affecting the salty or sweet taste.

凍結乾燥じゃがいも(凍みいも)の構成成分

凍結乾燥じゃがいも(凍みいも)の構成成分

Compositional and toxicological analysis of a GM potato line with reduced α-solanine content – A 90-day feeding study in the Syrian Golden hamster

Steroidal glycoalkaloids (GAs) are toxins, produced by plants of the Solanaceae family. The potato plant (Solanum tuberosum L.) and its tubers predominantly contain the two GAs α-chaconine and α-solanine. These compounds are believed to act in synergy, and the degree of toxicity may therefore depend on their ratio in the potato. To determine the influence of α-solanine: α-chaconine ratio in potatoes on toxicity, a GM potato line (SGT 9-2) with reduced α-solanine content, and the parental control line (Desirée wild-type) having a traditional α-solanine: α-chaconine ratio were (1) studied for compositional similarity by analysing for a range of potato constituents, and (2) used in a 90-day feeding trial with the Syrian Golden hamster to study differential toxicity. The animal feeding study used diets with up to 60% freeze-dried potato powder from either line. Whilst data indicated some compositional differences between the GM line and its wildtype control these did not raise concerns related to nutritional value or safety. Results of the feeding trials showed a low number of significant differences between potato lines with different α-solanine: α-chaconine ratio but none were considered to raise safety concerns with regard to human (or animal) consumption.