Chips of the old block

SM Paul Khurana analyses the transformation of the humble Indian potato into the crispest of chips or the perfect French fry and also discusses new hybrids

All across the world, potatoes are processed into value-added products like chips and French fries, which have longer shelf lives.
In developed countries, a major part of total production, 40-60 per cent, is consumed in processed form, while much less is used for home cooking or for livestock, and a very small percentage is used for the production of starch or alcohol. By contrast, in India, potatoes are mainly produced for domestic cooking.
Potatoes meant for processing require certain attributes, mainly relating to shape and size, external and internal defects, and most importantly, the proportion of dry matter, reducing sugars and phenols. While round, shallow-eyed tubers of 2.5-3 inches in diameter are preferred for chipping, larger, oval tubers of more than 3 inches in length are required to produce good quality French fry sticks. The dry-matter and reducingsugar content of potatoes are two very important biochemical considerations for the processing of potatoes. High dry-matter content and low reducing-sugar content result in higher production and a lighter colour of chips and French fries.
Potatoes meant for chips need to have more dry matter (greater than 20 per cent) and lesser reducing sugars (less than 150mg/100g of fresh produce), compared with French fries, which require relatively less dry matter (nearly 20 per cent) and more reducing sugars (less than 250mg/100g). Besides, potatoes meant for processing need to have low amounts of phenols so as to prevent enzymic discolouration upon peeling or blackening after cooking.

VARIETIES FOR POTATO CHIPS
The potato varieties produced in the country till 1997 were developed mainly for cooking purposes. These varieties generally have less dry matter (18- 19 per cent) and more reducing sugars (above 250mg/100g), and therefore, were not suitable for processing. Among these, two varieties, Kufri Jyoti and Kufri Lauvkar, have been identified by the chipping industry to be better than the others.
However, not all the produce of these varieties from various locations is suitable for processing. The produce from only a few of the warmer regions, like Indore and Ujjain in Madhya Pradesh, Nagrota at the foothills of Himachal Pradesh, and parts of central Uttar Pradesh consist of potatoes of acceptable quality for processing. Thus, despite the large quantities of potato available in the market, the supply of tubers of processable quality has been limited. Efforts to introduce European and North American processing varieties have also not been very successful, mainly because these varieties have been bred for long-day conditions, whereas the crop in India is raised mainly during the shorter winter days.
In view of this situation, the Central Potato Research Institute launched a programme in 1990 to breed varieties for processing. Its efforts have resulted in the development of India’s first potatoprocessing varieties: Kufri Chipsona-1 and Kufri Chipsona-2. Both varieties have a crop duration of about 100 days. Kufri Chipsona-1 produces oval, fleet-eyed tubers having cream-white flesh, whereas Kufri Chipsona-2 produces mid-sized, round to oblong, shallow-eyed tubers with flesh of a very-light-yellow hue. Both varieties are resistant to late blight, and Kufri Chipsona-2 is also tolerant to frost. These varieties yield, on an average, about 30-32 tonnes per hectare, which is at par or a bit more than Kufri Jyoti, but possess 2-4 per cent more dry matter, producing chips of excellent quality. The subcommittee on Crop Standards and Notification of Horticultural Varieties has recommended both the varieties for the purpose of commercial cultivation in the country.
In trials conducted in the Indo-Gangetic plains and central India, Kufri Chipsona-1 and Kufri Chipsona-2 had dry matter in the range of 19.5- 26.6 per cent, as compared to 16.4-25.7 for Kufri Jyoti. When test-fried in the laboratory, both varieties, from diverse agro-climatic conditions, produced excellent light-coloured chips.
These varieties have also demonstrated their superiority over Dutch varieties imported in the country for processing. While none of the Dutch varieties conformed to the parameters important for processing – crop duration between 90-110 days, yield equal to that of present-day processing variety, dry matter in the range of 21-22 per cent, and chip colour between grades 1-3 (1 being the lightest and 8 being dark-brown in colour) – both the Indian varieties met these requirements.
Both Kufri Chipsona-1 and Kufri Chipsona-2 store well at 12°C with treatment by chlorpropham (CIPC) to prevent sprouting, and compare well with the best American processing varieties – Frito Lay hybrid 1533 and Atlantic. In experiments conducted at Modipuram, Uttar Pradesh, Kufri Chipsona-1 and Frito Lay hybrid 1533 yielded chips of an acceptable colour after 30 days of....

contd...

TO READ FURTHER... SUBSCRIBE TO YOUR COPY TODAY!!!