Lye Peeling Research Articles

Flame-catalytic infrared dry system for tomato continuous peeling

To eliminate the need for alkali and excess water while accelerating the industrial application of dry tomato peeling, a highly efficient industrial flame-catalytic infrared continuous peeling apparatus was designed. The synthesis of the catalytic layer (Pt/Al2O3) within the device was optimized to improve cost-effectiveness and enable modular installation, making it suitable for industrial applications. This study determined the optimal production parameters for industrial flame-catalytic infrared peeling (F-CIP) through experiments. Current findings demonstrated that, under optimal F-CIP conditions, characterized by a flame heating time of 5.8 s, an infrared heating temperature of 456 °C, an infrared heating distance of 70.6 mm, and an infrared heating duration of 246 s, peeling efficiency reached 99.2±0.9 %, with a peel loss of 4.1±0.3 %. Comparative analysis with lye peeling (LP) and hot water peeling (HWP) showed that F-CIP reduced hardness and peel loss and better preserved nutritional and antioxidant compounds. The mechanism responsible for the loosening and cracking of the fruit skin in the F-CIP peeling process involved a reduction in adhesion between the skin and the pulp due to the alteration of the pectin structure, an expansion of cell structure due to internal vaporization, and an increase in the Young’s modulus of the tomato skin. The F-CIP method, with its proven peeling efficiency, energy-saving attributes, and environmentally friendly features, is expected to attract increased attention from equipment manufacturers and the tomato industry. This paper serves as a foundational guide and contributes to the application and parameter control of F-CIP in the tomato peeling.

Catalytic infrared radiation dry-peeling Technology for non-Frozen and Frozen Grapes: Effects on temperature, peeling performance, and quality attributes

This study introduces catalytic infrared radiation (CIR) heating technology as an eco-friendly alternative to conventional grape lye peeling (LP). The effects of heating time and distance on non-frozen and frozen grapes were assessed for temperature, peeling performance, and quality attributes. The findings indicate that CIR heating achieves complete dry-peeling of grapes. Extended heating times and reduced distances improve peeling performance, with more favorable results observed in frozen grapes compared to non-frozen ones. Grapes peeled using CIR demonstrated enhanced hardness, color, sugar-acid ratio, bioactive compounds, and antioxidant capacity, compared to those peeled using LP. Importantly, the frozen samples preserved their quality after CIR dry-peeling treatment. Based on peeling performance and quality attributes, the optimum heating times are established at 160 s for non-frozen grapes and 50 s for frozen grapes, at a heating distance of 5 cm. Therefore, CIR dry-peeling is recommended as an eco-friendly and quality-enhancing sustainable grape processing technology.

Isolation of Polyphenols from Two Waste Streams of Clingstone Peach Canneries Utilizing the Cloud Point Extraction Method

This study aimed to assess the feasibility of employing cloud point extraction (CPE) as an efficient way of extracting polyphenols from peach waste (PW). Four distinct food-grade surfactants (Genapol X-080, PEG 8000, Tween 80, and lecithin) were evaluated at concentrations ranging from 2–10% w/v to determine the efficiency of the technique in two separate PW streams [i.e., lye peeling waste stream (LPWS) and total wastewater stream (TWS)]. Low amounts (2% w/v) of surfactants in a single-step CPE were found to result in less than ~61% polyphenol recovery in LPWS and less than ~69% polyphenol recovery in the TWS, necessitating additional extraction steps. In both PW streams, the single-step polyphenol recovery was improved by 25–67% utilizing a higher amount of surfactants (5–10% w/w), leading to a statistically significant figure (p < 0.05). The CPE procedure was conducted under optimal conditions, including a temperature of 65 °C, a sodium chloride concentration of 3% w/v, a pH level of 3.5, and a surfactant concentration of 5% w/v. The polyphenol recovery was efficient when the CPE procedure was conducted twice. Tween 80 proved to be the most efficient surfactant among the four tested surfactants, achieving recoveries above 98% in both PW streams. Under optimum extraction conditions, the total polyphenol content and antiradical activity of PW extracts were evaluated. The results showed statistically significant differences (p < 0.05) between the two PW streams, with the LPWS having approximately 12 times higher polyphenol content and being more potent, achieving ~64% antiradical activity. Using the LPWS instead of the TWS is a more cost-effective and feasible option for the industry. In addition, the considerable volume of the TWS makes it challenging to handle and demands a correspondingly major amount of surfactant. Considering that Tween 80 is a low-toxicity surfactant and that the CPE method is simple, fast, cost-effective, highly accurate, and selective, the extracted polyphenols from two PW streams could be exploited as natural antioxidants to be used directly in the food industry. These findings could have major implications for the manufacturing of sustainable and naturally-derived food additives.

Impact of pulsed electric fields (PEF) treatment on the peeling ability of tomatoes and kiwi fruits

Peeling is a standard food processing operation that removes the outer layer of fruits and vegetables. It can improve the appearance and texture of many fruits and vegetables and is often necessary for further food preparation. Developing new and innovative peeling methods to minimise losses and enhance product quality is an area of active research in the food industry. The objective of this study was to evaluate how PEF affects the peeling ability of tomatoes and kiwi fruits, as well as the chemical and physical characteristics of the resulting peeled products. In detail, monopolar exponential decay pulses were applied, with an electric field strength of 1.0 kV/cm and a resulting total energy input in the range of 0.6 and 5.0 kJ/kg for tomatoes and 1.2 and 12.6 kJ/kg for kiwi fruits. Two methods were used to compare the effectiveness of PEF treatments with traditional peeling methods: hot-water blanching (98°C for 60 s) and lye peeling (98°C for 45 s, in 2% NaOH solution). The peeling efficiency was evaluated through manual and mechanical methods as well as measuring weight loss. The quality of the final peeled product was assessed by mechanical properties of the pericarp, colour (L*, a*, b* scale), ascorbic acid content, chlorophyll a and b, carotenoids, total polyphenols content and antioxidant activity. The PEF treatment applied to whole red tomatoes (1.0 kV/cm, 5.0 kJ/kg) and whole kiwi fruits (1.0 kV/cm, 12.6 kJ/kg) resulted in a significant decrease (p≤ 0.05) of up to 43% and 83% in the force required for mechanical peeling, respectively. The PEF treatment showed comparable or superior peeling ability and significantly reduced product losses compared to hot-water blanching and lye peeling methods. However, the softening and the weight losses tend to increase by increasing the pulses for both investigated matrices. Moreover, by applying PEF instead of blanching or lye peeling, the chemical quality and the colour were better preserved (ΔE < 2). This study proved that PEF could be a promising non-thermal technology to better peel tomatoes and kiwi fruits without affecting their final quality. Consequently, applying PEF as a treatment to facilitate peeling has remarkable potential as an industrial application to reduce energy consumption and issues related to wastewater management typically occurring during the peeling with lye agents.

Fine physicochemical, structural, rheological and gelling properties of tomato pectin under infrared peeling technique

To protect the pulp quality, the effect of infrared peeling on the physicochemical, structural, rheological, and gelling properties of tomato pectin was investigated using newly developed catalytic infrared peeling equipment and compared with manual, hot-water and lye peeling. Compared to manually peeled pectin, the results showed that hot-water peeling reduced the pectin yield by 13.19% but significantly increased the pectin's Z-average radius of gyration (Rg) and hydrodynamic radius (RH). And the pectin gel had excessive hardness. Lye peeling reduced the pectin yield by 30.43%, the degree of esterification (DE) by 25.97%, RH by 7.8 nm and Rg by 2.9 nm. And the pectin gel had the worst water-holding capacity and texture. The yield and DE of pectin (IPP) after infrared peeling only decreased by 3.88% and 0.9%. IPP exhibited moderate physicochemical, structural, rheological, and gelling properties, which was the closest to manually peeled pectin. IPP gel showed steady viscoelasticity and high water-holding capacity (96.71%). Conclusively, the infrared peeling technique can provide better pulp quality and is sustainable.

Chemical, structural and functional properties of pectin from tomato pulp under different peeling methods

To protect tomato pulp quality, this study investigated the effect of the infrared peeling method (using our newly developed catalytic infrared peeling equipment) on pectin's chemical, structural and functional properties and their correlation compared with manual, hot-water, and lye peeling methods. Infrared peeling significantly improved pectin’s emulsifying and antioxidant capacity compared to manual peeling by increasing branching degree. Hot water peeling significantly improved pectin’s viscosity, emulsifying and antioxidant capacity. However, the pectin chains had low flexibility. The effect of lye peeling on pectin was the greatest, causing the lowest linearity and the largest degree of branching. In comparison, infrared peeling had the least impact on pectin. It was further confirmed that pectin’ viscosity, emulsifying, and antioxidant capacity were highly correlated with its chemical and structural properties. In summary, the infrared peeling method provides better pulp quality and is more sustainable because no water and chemicals are used.

Research on tomato peeling using flame-catalytic infrared radiation

To improve tomato peeling rate and ensure pulp quality, a flame-catalytic infrared peeling (FIP) method was developed in this study. The peeling parameters, peelability, mechanism (polysaccharides, mechanical property, and microstructure) and pulp quality (firmness, lycopene, and polysaccharides) were investigated. Results showed that FIP under 10 s flame heating and 4 min infrared heating at 350 °C yielded the highest peelability (98%), firmness (6.04 g/mm2), and lycopene (53.73 mg/kg). Compared with hot water peeling (HWP) and lye peeling (LP), FIP had the least degradation of cellulose (92.32%), hemicellulose (61.75%), and pectin (76.47%) in peel and the least damage to their structures and mechanical properties with the reductions of 19.50% and 16.69% (tensile and puncture forces). The only cell collapse of the peel was found in FIP by scanning electron microscopy (SEM), showing a different peeling mechanism from the HWP and LP. In addition, FIP protected pulp quality to the greatest extent, which had the highest retention of cellulose (91.67%), hemicellulose (94.08%), pectin (98.66%), and firmness (6.04 g/mm2), significantly increased the lycopene content and did not change their structures. It proves that FIP has a promising potential to replace the existing peeling technology and can be widely applied in the fruit peeling.

Microwave-assisted infrared dry-peeling of beetroot: Peeling performance, product quality, and cell integrity

The use of low power-short time microwave (MW) treatment before infrared (IR) heating could help improve the peeling performance of beetroot. MW-assisted IR peeling (MWIR) and IR peeling of beetroot were investigated and compared with the conventional hot-lye peeling method. Also, the effects of these peeling methods on the quality and microstructure were evaluated. Hot-lye peeling at 95 °C for 40 s and 60 s was used as control. Results showed that MW-assisted IR peeling at power 640 W and heating time 7 min produced samples with the highest peelability (99.4%), lowest peel thickness (0.075 mm), and peel remaining (0.8%), lower peeling loss (4.23 g), and better peeling easiness when compared with lye peeling and IR peeling. IR peeling alone produced samples with the lowest peeling loss (2.87 g) and surface colour change, and the highest vitamin C retention (75.32%) than MW-assisted IR and lye peeling respectively. The product microstructure for the different peeling methods showed cellular distortion as a result of thermal expansion. MW pretreatment shows a promising potential to further develop the IR dry-peeling method, to replace the conventional hot lye chemical peeling.

Advances in peeling techniques for fresh produce

AbstractPeeling is a significant stage of post‐harvest processing of fruits or vegetables. The most adopted peeling methods are mechanical, steam, chemical, and manual peeling. Apart from these methods, some other methods such as enzymatic, infrared, and some methods like ohmic heating, ultrasound‐assisted lye peeling, and pulse electric field‐assisted steam peeling are also used. To concern the freshness of the product, manual peeling is the most ideal method but it consumes an inefficient amount of time and physical labor. Mechanical method consumes less time and under this process, the collected peel can be utilized in the by‐product stream. Lye peeling is an efficient method but the disposal of lye after the process is an environmental concern. Adjusting this system to include ultrasound, ohmic heating and CO2 laser drilling coupled with moderate electric fields can be used to reduce the lye requirement. Enzymatic peeling produces good quality products with low waste but can only be applied to fruits whose distinct separation of peel from the flesh is needed. PEF‐assisted steam peeling helps immensely in terms of cost‐saving by reducing the high use of steam. Infrared dry‐peeling only heats the superficial layer of fruits and possesses minimal effect in an edible inner portion of fruit. It uses less time with low peeling loss, high peelability, high peeling yields, thin skin is peeled‐off, but needs more research to justify industry implementation. In conclusion, the novel method assisted peeling can be used to save the time, environment, and quality of the fruit or vegetables.Practical applicationsPeeling is the primary post‐harvest process applies to the group of foods and it is crucial to have minimal damage to the products at this stage. For utilization of the peeling process in any processing, the knowledge of the all available and efficient peeling process for the individual fruit or vegetable is necessary. The main objective of the review is to outline the applicable current and novel peeling techniques for the commodities with their process conditions, mechanisms, advantages, and disadvantages.

Design and Fabrication of Small-Scale Potato Peeling Machine with Lye Method

Peeling or removing the skin is one of the main post-harvest processes in fruits and vegetables. At present, most of the peeling of fruits and vegetables is done manually using sharp objects / knives. This method of peeling causes more fruit flesh to be wasted, especially fruits / vegetables with thin skins. Therefore, the design of a machine that can peel thin-skinned fruits / vegetables using the lye peeling method is needed. The purpose of this study was to design and fabrication a machine that can peel fruits and vegetables after the pre-treatment process of soaking in hot NaOH. The way this machine works is by spraying pressurized water on the fruit soaked in hot NaOH solution. In this study, the object was potatoes. Control of water pressure coming out of the nozzle is done using the pulse width modulation (PWM) method with a potentiometer. The treatments were carried out using three duty cycle values with the analogue input setting value on the microcontroller which resulted in three variations of water pressure coming out of the nozzle, namely: 60% (4.2038 Pa); 80% (5.6051 Pa); and 100% (7, 0065 Pa). Respectively for low, medium and high levels. Treatment concentrations of NaOH were 9%, 11% and 13%. The results obtained were the percentage of perfectly peeled skin close to 100% was obtained at 11% NaOH with a duty cycle value of 60% and 80%; and 13% NaOH with a duty cycle value of 80%. The calculation of the smallest percentage weight loss is 14.96% at 9% NaOH duty cycle 100% and the highest percentage weight loss is 35.89% at 13% NaOH 80% duty cycle.

Pear peeling using infrared radiation heating technology

Infrared radiation (IR) heating could be a potential alternative peeling method to address the long-term water supply and wastewater disposal issues involved in the conventional lye peeling process of pears. The objective of this study was to investigate the feasibility of IR peeling technology as an environmentally friendly alternative practice to efficiently produce peeled pear products with superior quality and yield. A pilot IR Dry-Peeling System consisting of catalytic IR emitters, roller conveyor, and peeler remover was developed and used for this research. Effects of the pear firmness and heating time on the peeling performance and product quality were studied. Under the continuous loading condition, the most desirable peeling result was achieved for Bartlett pears in the initial firmness range of 22 to 31 N after 99 s of IR heating. The results of IR peeling indicated superior product quality with relative thin cooking ring (0.76 ± 0.20 mm), limited peeling loss (9.25 ± 1.25%), and fairly ease of peeling (5.33 ± 1.00). According to SEM photomicrographs of pericarp cross-section, IR heating caused loss of integrity and compartmentalization of cells of the hypodermal layer to only “ripe” pears (firmness of 26.5 ± 2.8 N). Thermal effect of IR heating dramatically disrupted the middle lamella of hypodermal cells and resulted in mechanical failure of those cells and subsequent layer loosening of “ripe” pears.

Viscoelastic properties of tomato peels produced from catalytic infrared and lye peeling methods

This study investigated the effect of infrared and lye peeling methods on viscoelastic properties of tomato peels of cultivars - Hz 5508, Seminis DRI 319, and Seminis HP 849 using a dynamic mechanical analyzer (DMA) under temperature ramp mode. Peels were produced from infrared (IR) peeling conducted at three tomato surface temperatures of 109, 112 and 115°C, and lye peeling conducted at 95°C using a 10% NaOH solution. Fresh tomato peels were used as a control. It was found that dynamic moduli of all the peel samples decreased initially and then increased with increase in temperature, displaying a parabolic curve. Storage moduli of peel samples were higher than their respective loss moduli, indicating dominant elastic properties over viscous properties in tomato peels. Compared with the control, IR and lye treated peels had higher and lower storage moduli, respectively. Raw peels had significantly (α=0.05) higher transition temperatures (89.4°C) than the IR (72.2°C) and lye (46.2°C) treated peels. Storage moduli at respective transition temperatures were significantly (α=0.05) higher for IR treated peels (9.8MPa) than those of raw (4.4MPa) and lye treated peels (1.0MPa). The storage moduli of Seminis DRI 319 and Hz 5508 at respective transition temperatures were not significantly different (α=0.05). However, they were significantly (α=0.05) lower than those of Seminis HP 849. The difference in storage moduli and transition temperatures of tomato peels obtained from IR and lye peeling processes indicated a fundamental difference in their peeling mechanism.

Effect of Pre-Treatment on The Physicochemical Characteristics of Potato Powder Dried by Drum Dryer

In the industrial processing of fruits and vegetables, such as potato, the peeling and blanching processes are considered as pre-treatment. The choice of the most appropriate treatment depends on the raw material and the necessary attributes for the final product. This study aimed to determine the effect of pre-treatment (peeling and blanching method) on the physicochemical characteristics of potato powder dried by drum dryer. In this study, Margahayu variety was used. Potatoes were sorted, peeled (no peeling, abrasive, lye, and hand peeling method), soaked in clean water, cut into four parts, drained, and then blanched for 10,15, and 20 minutes. Blanched potatoes were subsequently mashed into a paste and then dried by drum dryer. The physicochemical character of potato powder was analyzed, i.e. yield and colour, water, ash, fat, protein, and carbohydrate content. The results showed that peeling and blanching treatment had a significant effect on yield, colour, water and protein content, and had no significant effect on ash, fat, and carbohydrate content. Treatment of lye peeling with blanching for 10 minutes resulted in the best of yield (17.8%) and powder physicochemical characteristics such as colour (L=95.30; a=0.36; b=28.83), water content 7.18%, ash 3.25%, fat 0.36%, protein 10.14 %, and carbohydrate 80.80%.

Quasi-static mechanical properties of tomato peels produced from catalytic infrared and lye peeling

This study investigated the quasi-static mechanical properties of tomato peels of three cultivars - Hz 5608, Seminis DRI 319 and Seminis HP 849. The peels were produced from infrared (IR) heating with three targeted tomato surface temperatures of 109, 112 and 115 °C at two loading rates which reflected the different heating rates. Peels from conventional lye peeling method using a solution of 10% NaOH at 95 °C were used for comparison. Fresh tomato peels were used as control. A texture analyzer was used to determine the tensile strength to failure, puncture resistance strength, and adhesive strength of peels. It was found that mechanical strengths of tomato peels obtained from both IR and lye peeling processes were significantly (α = 0.05) lower than those of the control. However, the mechanical strengths of tomato peels under IR treatment at the temperatures of 109 and 112 °C were significantly (α = 0.05) higher than those of the peels obtained from lye treatment. The mechanical strength of the peels produced from IR treatment at 115 °C was similar to those produced from lye treatment. The reductions in tensile, puncture and adhesive strengths of peels were up to 88, 87.3 and 74.3%, respectively, for IR heated tomatoes, whereas these were 95.1, 99.3 and 91.3%, respectively, for lye treated tomatoes compared to control. The peels obtained from IR peeling had more integrity than those obtained from lye peeling. Increasing the loading rates of tomatoes during IR heating corresponding to lowered heating rate significantly (α = 0.05) decreased the mechanical strengths of peels due to increased residence time for reaching the targeted temperatures. Tomato cultivars had a significant (α = 0.05) effect on the adhesive strength of peel but not on tensile and puncture resilience strengths. These results provide important information about the changes of mechanical properties of tomato peel under different processes.

Tomato peeling performance under pilot scale catalytic infrared heating

Steam and lye peeling methods have been the most commercialized methods in tomatoes industry. However, they are water and energy intensive and have adverse effects on the environment. The infrared (IR) dry-peeling was studied as a sustainable tomato peeling method because it does not require water nor chemicals. An IR peeling system equipped with catalytic IR emitters was designed and constructed. The peeling performance of the system, in terms of peelability, peeling loss, and product quality, was examined under different loading rates using the tomatoes cultivars, Hz 5608, Seminis DRI 319, and Seminis HP 849. Peeling performance was significantly (α = 0.05) affected by surface temperature of tomatoes during IR heating. A tomato surface temperature range of 109–115 °C (±2 °C) during IR heating was found to be optimum for achieving a good peeling performance. Compared to conventional lye peeling, IR dry-peeling produced up to 38.2% firmer peeled tomatoes and up to 12.2% lower peeling loss with a similar or better peeling easiness and more desirable color of the peeled tomatoes.

Peeling of kiwifruit using infrared heating technology: A feasibility and optimization study

Infrared (IR) technology has been studied as an alternative to conventional food processing technologies. The IR technology has attractive merits such as uniform heating, high heat transfer rate, reduced water, and energy consumption and improved product quality and safety. This research studied the feasibility of kiwifruit peeling using IR heating. The response surface methodology (RSM) was used to investigate the effects of IR radiation power (250–850 W), the distance between IR emitter and sample (10–70 mm) and heating time (45–125 s) on the peeling performance and physicochemical properties of kiwifruit. Lye-peeling was used as the control treatment to compare the efficiency of IR peeling. Heating with a power of 446 W at the distance of 70 mm for 125 s was found to be the optimum operating conditions for the IR peeling of kiwifruit. Under these conditions, the results were a peelability of 90%, weight loss of 4.5%, peel thickness of 0.4 mm, surface temperature of 64.1 °C, puncture force of 57.7 N, color difference of 2.4 and ascorbic acid content of 140 mg/100 g fresh fruit. Compared to hot lye peeling, the IR radiation heating caused significant reduction in weight loss, surface temperature, and color differences. It also maintained the firmness of fruits.

Development and optimization of novel infrared dry peeling method for ginger (Zingiber officinale Roscoe) rhizome

Abstract The novel infrared dry-peeling method was developed as an alternative to the conventional lye and abrasion peeling of ginger rhizome. The experiments on infrared dry-peeling of ginger rhizome were conducted to eliminate the use of water and chemicals in peeling process, enhance the quality of peeled rhizomes and make it a sustainable method. The effects of operating parameters like infrared temperature (300°–400 °C), product to IR heater spacing (10–30 mm) and exposure time (120–300 s) on the peeling performance were investigated. The multiple response optimization was carried out using response surface methodology. The optimum conditions were obtained at 300 °C infrared temperature, 21 mm spacing and 120 s exposure time which resulted in the peeling percentage of 92.77%, 90.40% peelability, 6.94% peeling loss and unpeeled percentage of 9.6. The comparative study of optimized infrared assisted peeling with conventional abrasion and lye peeling showed that infrared dry-peeling results in lower peeling losses. The SEM images of peels showed that IR radiation causes the desirable changes in elastic and other textural properties of the peel.

A novel two-step ultrasound post-assisted lye peeling regime for tomatoes: Reducing pollution while improving product yield and quality

In this paper, the effects and mechanisms of a novel two-step tomato peeling method, hot lye with a post-assistance of ultrasound, were investigated. The present work aims to improve the environmental friendliness of the conventional hot lye tomato peeling method (10% w/v, 97 °C, 45 s). The results showed that 4% (w/v) lye treatment at 97 °C for 30 s with a post-assistance of a 31.97 W/L ultrasound treatment at 70 °C for 50 s achieved a 100% peelability. In this scenario, the peeling yield and lycopene content in the peeled product were significantly higher than the peeling yield and lycopene content with the conventional hot lye peeling method. The present two-step peeling method was concluded with a mechanism of chemico-mechanical synergism, in which the hot lye functions mainly in a chemical way while the ultrasound is a mechanical process. Especially from the lye side, this work first demonstrated that the lye penetrated across the tomato skin via a pitting model rather than evenly. The findings reported in this paper not only provide a novel tomato peeling method with significant environmental benefits but also discover new clues to the peeling mechanism using hot lye.

Ohmic Heating Assisted Lye Peeling of Pears.

Our work shows that lye concentrations can be greatly reduced while peeling pears, resulting in significant savings in use of caustic chemicals, reduced costs for effluent treatment and waste disposal.

Ultrasound-assisted lye peeling of peach and comparison with conventional methods

Abstract In the present study, ultrasound-assisted lye peeling (ULP) was applied in peaches (Prunus persica L. Batsch) and compared with other methods. Different lye concentrations, ultrasonic power density, peeling time and temperature were investigated during ULP process. To evaluate peeling effectiveness, peeled thickness, peeling loss, peach color and peeling performance score were determined. The effects of ULP on quality of peaches were also considered to determine the optimum peeling process. As a result, Lye concentration of 0.50 mol/L combined with a power density of 270 W/L for 90 s at 90 °C demonstrated the optimal peeling effectiveness. Compared with manual peeling, hot water peeling (90 °C, no lye), ultrasound-assisted hot water peeling (90 °C, no lye, 270 W/L) and lye peeling (90 °C, alkali concentration of 0.50 mol/L), ULP showed the highest peeling performance score accompanied with appropriated peeling loss and peeled thickness. The color, soluble solids and titratable acidity for ULP peaches showed slight difference from peaches peeled by other methods. Industrial relevance Traditional peeling methods especially LP not only led to excessive loss of pulp but also damaged the environment to a great extent. Ultrasound as a green technology enhanced mass transfer and heat transfer, further promoting the efficiency of peeling process. In this study, ULP showed higher peeling performance with reduced peeling time, and the peaches quality was guaranteed, demonstrating the potential of ULP as an alternative to conventional peach peeling methods.