Optimization of ultrasonic-assisted enzymatic extraction of kiwi starch and evaluation of its structural, physicochemical, and functional characteristics

A new source of starchy flour: Physicochemical and nutritional properties of starchy kiwifruit flour

The physicochemical and nutritional properties of three starchy kiwifruit flour (SKF) were systematically studied. The results revealed that the total starch content of SKF was 66.63-80.42%. SKF showed a B-type crystal structure with a grain size between 7.08 and 9.02 μm. In comparison to corn starch and potato starch, SKF possessed a lower pH (3.43-4.28), transparency (0.68-1.11%) and setback value (0.20-1.73 Pa·s) and a higher swelling power (9.42-15.02 g/g) and hot paste viscosity (1.73-2.10 Pa·s). Moreover, SFK was rich in protein and various mineral elements. It also contained high levels of total phenolics and exhibited a strong antioxidant capacity. The resistant starch content in SKF was as high as 67.19-73.22%, and the rapidly digestible starch content was remarkably lower than that of corn and potato starch. Overall, these unique physicochemical properties of SKF, coupled with its nutritional benefits, give it a good development potential in the food industry.

Optimization of ultrasound-assisted extraction of fatty acids from royal jelly and its effect on the structural and antioxidant property

Fatty acids are the key active components in royal jelly (RJ) with various biological activities. In this study, a novel ultrasound-assisted extraction (UAE) method was established to extract fatty acids from RJ and their structural and antioxidant property were further evaluated. The optimum extraction conditions were as follows: liquid-to-solid ratio of 10:1, ultrasonic power of 450 W and ultrasonic duration of 20 min, resulting in a better extraction yield of 16.48 % and 10-hydroxy-2(E)-decenoic acid (10-HDA) content of 4.12 %. Furthermore, compared with the solvent extraction method, the antioxidant activity of extract by ultrasound was enhanced significantly by at least 448 %. GC-MS showed that ultrasound didn't change the chemical composition of fatty acids, while it significantly increased the content of fatty acids. SEM image illustrated that extracts by UAE showed a rougher, looser microstructure compared to the solvent method. Overall, UAE is a promising method to obtain fatty acids in RJ with high efficiency.

Effect of partial substitution of wheat flour with kiwi starch on dough rheology, microstructure, the quality attributes and shelf life of Chinese steamed bread

Chinese steamed bread (CSB), a conventional high-GI staple food, with a short shelf life and a single flavor. In this work, 10-20 % kiwi starch (KS) was used to substitute wheat flour for the production of CSB and the effects of different substitution ratios on the quality and shelf life of mixed flour, dough, and CSB were explored. The results showed that the substitution of KS could improve the water binding capacity of mixed flour and lead to easier pasting in the system, lower the cooking power consumption, increase and improve the viscoelasticity and gas holding capacity of the dough, and make the microstructure more compact and uniform. As the substitution ratio increased, the reduction in protein content within the system further affected the formation of the gluten network, leading to a significant decrease in the CSB's specific volume and cohesiveness, whereas the chewiness and hardness were significantly improved. Meanwhile, KS substitution significantly reduced the starch hydrolysis rate and estimated glycemic index of CSB. 10 % KS substitution enriched the aroma and color of CSB, improved its internal organizational structure, and became more popular among consumers. A substitution ratio of 15-20 % was beneficial for extending the shelf life of CSB.

Ultrasound-assisted enzyme extraction and properties of Shatian pomelo peel polysaccharide

In this study, Shatian pomelo peel was used as the raw material for extracting polysaccharides using hot water extraction (HW) and ultrasonic-assisted enzyme (UVE) methods, respectively. The optimal parameters for extractingShatian pomelo peel polysaccharides (StPP) using the ultrasound-assisted enzymatic method were determined using response surface methodology (RSM). The optimal conditions for the extraction of StPP were as follows: ultrasound power 350 W, ultrasound time 50 min, enzymatic digestion time 50 min, compound enzyme addition 1.5%, and enzymatic digestion temperature 55 °C. The yield of StPP was found to be 30.1310% under these conditions. Comparing the physicochemical properties and antioxidant activity of StPP extracted using different methods, it was observed that ultrasound-assisted enzyme extraction resulted in higher yield, sugar content and glucuronic acid content of StPP compared to traditional hot water extraction. Additionally, StPP extracted by ultrasound-assisted enzyme extraction showed better antioxidant activity. These results suggest that ultrasound-assisted enzymatic extraction is an effective method to enhance the activity of natural polysaccharides.

Physicochemical properties and in vitro digestibility of highland barley starch with different extraction methods

The objective of this study was to compare the structural, thermal, rheological and digestive properties of highland barley starch (HBS) by different extraction methods. Five techniques were used to extract HBS: Alkali extraction, Ultrasound extraction, double enzyme extraction (DE), three enzyme extraction (TE) and ultrasonic assisted TE (U-TE). The results indicated that the Ultrasound extracted HBS had fewer Maltese crosses, lower molecular weight (Mw), and higher content of damaged starch (P < 0.05). Meanwhile, DE extracted HBS had higher Mw, and the content of short amylopectin than that of Alkali extracted HBS (P < 0.05). Additionally, the DE extracted HBS showed the highest relative crystallinity and good short-range ordered structure, which led to the outcome of stronger thermal stability and higher values of G' and G'' (P < 0.05). These results indicated that enzymatic extraction could better protect the resistance of HBS by protecting its physicochemical properties.

Ultrasound-Assisted Extraction of Mango (Mangifera indica) Kernel Starch: Chemical, Techno-Functional, and Pasting Properties

(1) Background: Starch is the main component of mango (Mangifera indica) kernel, making it an alternative to obtain an ingredient from a non-conventional source with potential application in food and other industrial applications; however, reports on the use of new extraction techniques for this material are scarce. The main objective of this research was to evaluate the effect of ultrasound-assisted extraction (UAE) on the yield, chemical, techno-functional, rheological, and pasting properties of starch isolated from a non-conventional source such as a mango kernel. (2) Methods: Different power sonication conditions (120, 300, and 480 W) and sonication time (10, 20, and 30 min) were evaluated along with a control treatment (extracted by the wet milling method). (3) Results: Ultrasound-assisted extraction increases starch yield, with the highest values (54%) at 480 W and 20 min. A significant increase in the amylose content, water-holding capacity, oil-holding capacity, solubility, and swelling power of ultrasonically extracted starches was observed. Similarly, mango kernel starch (MKS) exhibited interesting antioxidant properties. The sol-gel transition temperature and pasting parameters, such as the breakdown viscosity (BD) and the setback viscosity (SB), decreased with ultrasound application; (4) Conclusion: indicating that ultrasound caused changes in physical, chemical, techno-functional, rheological, and pasting properties, depending on the power and time of sonication, so it can be used as an alternative starch extraction and modification technique, for example, for potential application in thermally processed food products such as baked goods, canned foods, and frozen foods.

Effect of autoclave-cooling cycles combined pullulanase on the physicochemical and structural properties of resistant starch from black Tartary buckwheat

A starch-rich portion is produced as a by-product of black Tartary buckwheat processing. The effect of enzymatic combined with autoclaving-cooling cycles (one, two, or three times) on the physicochemical and structural properties of black Tartary buckwheat type 3 resistant starch (BRS) was evaluated. The autoclaving-cooling cycles enhanced solubility and reduced swelling, with the BRS content increasing from 14.12% to 25.18%. The high crystallinity of the BRS reflected a high molecular order. However, increasing the number of autoclaving-cooling cycles did not result in higher BRS content. The highest BRS yield in the autoclaved starch samples was 25.18% after double-autoclaving-cooling cycles. Furthermore, the autoclaving-cooling cycles altered the crystalline structure of black Tartary buckwheat, and the subsequent crystallinity changed from 36.33% to 42.05% to 38.27%. Fourier-transform infrared spectroscopy shows that the number of cycles results in more efficient double-helical packing within the crystalline lamella. Principal component analysis showed that the autoclaving-cooling cycle treatment leads to significant changes in the molecular structure of resistant starch (RS). These results indicated that autoclaving-cooling cycles might be a feasible way for producing RS from black Tartary buckwheat starch with better structural stability to expand their application range.

Ultrasound-Assisted Extraction and the Encapsulation of Bioactive Components for Food Applications

Various potential sources of bioactive components exist in nature which are fairly underutilized due to the lack of a scientific approach that can be sustainable as well as practically feasible. The recovery of bioactive compounds is a big challenge and its use in food industry to develop functional foods is a promising area of research. Various techniques are available for the extraction of these bioactives but due to their thermolabile nature, there is demand for nonthermal or green technologies which can lower the cost of operation and decrease operational time and energy consumption as compared to conventional methods. Ultrasound-assisted extraction (UAE) is gaining popularity due to its relative advantages over solvent extraction. Thereafter, ultrasonication as an encapsulating tool helps in protecting the core components against adverse food environmental conditions during processing and storage. The review mainly aims to discuss ultrasound technology, its applications, the fundamental principles of ultrasonic-assisted extraction and encapsulation, the parameters affecting them, and applications of ultrasound-assisted extraction and encapsulation in food systems. Additionally, future research areas are highlighted with an emphasis on the energy sustainability of the whole process.

Optimization of Corn Resistant Starch Preparation by Dual Enzymatic Modification Using Response Surface Methodology and Its Physicochemical Characterization

Corn starch was dually modified using thermostable α-amylase and pullulanase to prepare resistant starch (RS). The concentration of starch liquid, the amount of added thermostable α-amylase, the duration of enzymatic hydrolysis and the amount of added pullulanase were optimized using RSM to increase RS content of the treated sample. The optimum pretreatment conditions were 15% starch liquid, 3 U/g thermostable α-amylase, 35 min of enzymatic hydrolysis and 8 U/g pullulanase. The maximum RS content of 10.75% was obtained, and this value was significantly higher than that of native corn starch. The degree of polymerization (DP) of the enzyme-modified starch decreased compared with that of native starch. The scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were performed to assess structural changes in native and pretreated starch. The effect of dual enzyme pretreatment on the structure and properties of corn starch was significant. Unlike the untreated one, the pretreated corn starch showed clear pores and cracks. Significant differences in RS contents and structural characterization between starch pretreated and untreated with dual enzymes demonstrated that the dual enzyme modification of corn was effective in enhancing RS contents.

Modification in structural, physicochemical, functional, and in vitro digestive properties of kiwi starch by high-power ultrasound treatment

Kiwi starch (KS) is a fruit-derived starch; in order to improve its processing performance and increase its added value, it is necessary to modify KS to enhance the positive attributes and to enlarge its application. In this study, KS was modified by high-power ultrasound treatment (HUT) to reveal the relationship between the structure and function of KS with different treatment powers (0, 200, 400, and 600 W) and different treatment times (0, 10, 20, and 30 min). The results showed that HUT destroyed the granular morphology of KS, formed holes and cracks on the surface, and reduced the particle size and the short-range molecular order of KS. After different HUTs, the apparent amylose content (AAC), swelling power (SP), water solubility index (WSI), viscosity and setback value (SB) of KS were significantly increased, while the gelatinization temperature was significantly decreased. In addition, HUT significantly reduced the content of rapidly digestible starch (RDS) and slowly digestible starch (SDS), while it significantly enhanced the content of resistant starch (RS) (64.08-72.73%). In a word, HUT as a novel physical modification method for KS, enlarged its application, and fulfilled different demands of a starch-based product, which introduces another possibility for kiwi fruit further processing.