Frying Equipment and Frying Oil Management: Sweet Potato Balls and Croquettes
Which Products Go to Frying?
Night-market sweet potato balls, crispy taro balls, croquettes, and fried tangyuan are mostly mass-produced along the lines of "portioning or encrusting → frying → cooling → packaging or quick freezing." Upstream, machines like Dong-Yih Machinery's Sweet Potato Ball and Taro Ball Portioning and Cutting Machine DY-528MS, listed on our website at 3,000–12,000 pieces per hour and 10g–30g per piece or heavier, cut the dough into uniform small balls; downstream, the frying equipment determines the color, texture, and oil absorption of the finished product.
Batch Fryers vs. Continuous Fryers
- Batch fryers: Fry one basket at a time, relying on people to judge when to lift it out. The equipment is simple and switching products is easy; suited to shops with small volumes and many products.
- Continuous fryers: Products are placed on a mesh conveyor belt and travel submerged through an oil bath, with frying time set by the belt speed; often an upper and lower belt hold the product below the oil surface for even browning. Suited to high-volume production of a single product.
- Options: filtration systems (continuously filtering out crumbs), exhaust hoods, automatic oil top-up, discharge draining conveyors, and so on.
The advantage of continuous fryers is that every piece is heated the same way, and staff don't have to work next to hot oil for long periods; the drawback is the large oil tank and high cost of changing oil, which doesn't pay off when volume is insufficient.
Oil Temperature Control
Oil temperature is the core variable in frying:
- Oil too cool: The crust takes too long to set, the product absorbs a lot of oil and tastes greasy, and sweet potato balls don't puff up easily.
- Oil too hot: The surface browns or even burns quickly while the inside isn't cooked through, and the oil degrades faster.
- Too much product at once: Oil temperature drops instantly, and color and texture become inconsistent.
In practice, find the oil temperature range and time suited to your product and fix them, and periodically check the controller's reading with a thermometer; with continuous equipment, keep the feed rate steady to avoid large swings in oil temperature.
Frying Oil Regulations
Article 5 of the Regulations on Good Hygiene Practice for Food (食品良好衛生規範準則) requires food businesses' hygiene management of "edible oil used for frying" to comply with Annex 2. Point 5 of Annex 2 is very clear: when the total polar compounds content of frying oil reaches 25%, it must be completely replaced with new oil and may not be used further. Total polar compounds are the sum of chemically polar compounds produced when oil breaks down or polymerizes during heating; the higher the value, the more degraded the oil.
In addition, a 2013 press release from the Ministry of Health and Welfare noted that during inspections, local health bureaus first use acid value as a preliminary test, and oil with an acid value above 2.0 is then sampled for total polar compounds.
Day-to-day management:
- Test regularly: Use a total polar compounds meter or test strips, and record the date, time, and reading.
- Record oil changes: Keep a record every time you change or top up oil. Article 11 of the Regulations requires records made under them to be kept for at least 5 years.
- Remove crumbs: Crumbs left in the oil accelerate degradation, so skim or filter them regularly.
- End-of-day handling: Once the oil has cooled, cover the tank to keep out dust and moisture.
- Waste oil: Have it handled by a qualified contractor in accordance with waste regulations.
Safety Reminder
Hot oil burns and fires are the biggest risks in the frying area. Don't let water or large amounts of frozen product drop directly into hot oil; clean grease buildup in exhaust hoods and ducts regularly; keep fire extinguishing equipment near the frying area but not in the walkway right next to the hot oil. Before cleaning the oil tank, stop the machine, cut the power, and wait for the oil to cool.
FAQ
Q: How often should frying oil be changed?
A: The regulations look at how degraded the oil is, not time. Under Annex 2 of the Regulations on Good Hygiene Practice for Food, it must be completely replaced once total polar compounds reach 25%.
Q: Can I just top up with new oil instead of changing the old oil?
A: When total polar compounds reach 25%, the rule is "completely replace with new oil," and topping up can't substitute for changing it.
Q: Why do my sweet potato balls come out flat instead of puffing up?
A: It may be oil temperature, dough recipe, or portion weight; first confirm the oil temperature is stable and each piece weighs the same, then adjust the recipe.
Q: Can Dong-Yih's sweet potato ball machine connect to a fryer?
A: The DY-528MS handles portioning and cutting; for downstream pairing, call us at 06-257-4644.