Sweet Sorghum Syrup can partially replace sugar or liquid glucose in various food and beverage applications

1. Abstract
This study describes a new method to produce clarified sweet sorghum juice using filter-aid and vacuum filteration
system. The juice is clarified and processed into syrup. The syrup is innovatively used as a sugar replacement or
ingredient in developing value-added food products, developed as per the Indian food regulations. Evaluation of
these food products showed that the samples were acceptable to the consumers and rated at par with commercially
available samples. These products are ready for commercialization.
Introduction
XX Sweet Sorghum [Sorghum bicolor (L.) Moench] belongs to kingdom Plantae, family Poaceae and genus
Sorghum. Sweet sorghum is a smart crop as it has multiple uses.
XX Sweet sorghum juice, obtained from low water consuming, short duration and seed-propagated sweet sorghum
plant, is a suitable source of syrup.
XX Sweet sorghum syrup can be used in the preparation of food products.
XX The syrup is thus a natural source for effective sugar replacement in bakery items, energy bars, breakfast
cereals, sugar confectionery, fruit and vegetable- based products and beverages.
XX Cultivation of sweet sorghum and further value addition offers farmers an excellent opportunity to improve farm
income and productivity in the semi-arid-tropics.
XX A study was undertaken to explore and demonstrate the innovative usage of sweet sorghum juice in the food
industry, which focused both on improving the processing of juice to food-grade syrup and the development of
value-added sweet sorghum syrup-based food products.
Processing
Extraction of sweet sorghum juice
XX Sweet sorghum variety ICSV 25274, grown in postrainy season during the year 2009 at
ICRISAT farm was harvested at physiological maturity.
XX Juice was extracted from its stalks using a horizontal three roller crusher (Jagadish No.
6, Gujarat, India).
XX The collected juice was pre-heated for about 20 minutes to 70°C, then cooled down to
40°C.
XX The juice was clarified using vacuum filtration – A filter cloth was cut to size and placed
on the the Buchner funnel.
XX A uniform bed of Celite® was prepared on the filter cloth,
XX The juice was then poured on the Celite® bed and filtered under vacuum. This process
resulted in clarified sweet sorghum juice.
XX The juice was concentrated to syrup by heating and slow evaporation. This was carried
out under uniform heating conditions with continuous stirring.
XX As concentration proceeded, the boiling point increases. Hence it is important to heat
under a low flame to avoid charring.
XX Scum formed was continuously removed.
XX Heating was stopped when the concentrated juice (syrup) was 72° to 76° Brix (Fig. 1).
Innovative Use of Sweet Sorghum Juice
in the Food Industry
Saikat Datta Mazumdara
*, A Poshadria
, Ch Ravinder Reddyb
, P Srinivasa Raob
, and Belum VS Reddyb
a
NutriPlus Knowledge Program, Agri-Bussiness and Innovation Platform (AIP), International Crops Research Institute for Semi-Arid Tropics
(ICRISAT), India, b
Research Program – Dryland Cereals, International Crops Research Institute for Semi-Arid Tropics (ICRISAT), India.
*Corresponding author: Tel: +919000686852; Fax: +914030713785; E-mail: s.dattamazumdar@cgiar.org
Advantages in product development
XX The syrup obtained from sweet sorghum juice contains biologically active substances and micro-nutrients.
XX It is a rich source of calcium, potassium and iron, and of natural antioxidants (ascorbic acid and other
carotenoids).
XX It does not easily crystallize into sugar because of its relatively higher content of reducing sugars as compared to
cane sugar.
XX Product developers can therefore explore the use of sweet sorghum syrup in applications where crystallization is
an issue.
XX The study proves that Sweet sorghum syrup can be used in the preparation of a number of food products without
compromising on their sensory quality.
Sweet sorghum syrup is shelf-stable:
XX As the syrup contains 70% or more of sugar, it is shelf-stable and does not ferment. The sugars present in syrup
bind most of the available free water thus reducing the water activity (aw
), leaving very little water for microbial
growth.
XX It is also an acidic food (pH<4.6). Thus sweet sorghum syrup with aw
between 0.6 to 0.65 and pH 3.75-4.00, is a
shelf-stable product without need for preservatives or refrigeration.
Sweet sorghum syrup for the pharmaceutical industry:
Sweet sorghum syrup can be used as an ingredient in Neutraceutical formulations, Medicated sweets, Blended powders,
Syrups, Elixirs, Tablets, Lozenges and Capsules.
Sweet sorghum syrup based products
Jan 2011
Harvesting the sweet
sorghum crop (proper
stage of maturity)
Crushing of sweet
sorghum stalks and
primary filtration
Pre- heating of juice
(70°C)
Clarification (Vacuum
filtration/ Filter press with
filter aid Celite®)
Clear clarified sweet
sorghum juice
Concentration to Syrup
(75°Brix)
Value-added sweet
sorghum syrup based
products
Fig. 1. Steps involved
in processing of sweet
sorghum juice to
syrup for further value-
addition.
Conclusion
XX Efforts are focused on establishment and promotion of small-scale decentralized sweet sorghum crushing and
syrup making enterprises in rural areas.
XX The aim is to reduce poverty and improve livelihoods of smallholder farmers. Through this study, NutriPlus
Knowledge Program, Agri-Bussiness and Innovation Platform (AIP)@ICRISAT has successfully developed sweet
sorghum syrup-based food products with complete or partial replacement of sugar with sweet sorghum syrup.
XX NutriPlus shall further conduct workshops and entrepreneur development programs on establishing and
managing commercial sweet sorghum syrup enterprises and partner with the public and private sector to promote
these products.
Ready-To-Serve (RTS)
Sweet sorghum-based
beverage
Sweet sorghum-based
waffle syrup
Tamarind- Sweet
Sorghum Sauce
Sweet sorghum-based
energy bar
Sweet sorghum based granola bar
Sweet sorghum-based
tomato sauce
Multi-grain cookies with
sweet sorghum syrup
Sweet sorghum-based
mixed‑fruit jam
Sweet sorghum-based toffee Sweet sorghum crispies
Analysis
Physico-chemical characteristics:
XX Total soluble solids (°Brix) and pH of juice, syrup and the developed beverages were measured with a digital
pocket refractometer and pH meter, respectively.
XX Acidity was calculated by titrating against 0.1 N NaOH and expressed as percentage of citric acid. Water activity
(aw
) was measured using a water activity meter (Table 1).
Table 1.
Sweet Sorghum
products
º Brix Water activity (aw
) PH Acidity
(as % citric acid)
Juice 18.0±0.05 0.99±0.01 5.17±0.02 0.28±0.36
Syrup 73.0±0.07 0.65±0.02 3.75±0.034 2.34± 0.13
Squash 40.0±0.03 0.95±0.02 2.54±0.052 1.2± 0.43
RTS beverage 10.0±0.06 1.0±0.00 4.00±0.01 0.4±0.02
Nutritional analysis:
XX Crude protein, total ash, ascorbic acid content, reducing sugars and total sugars were determined (Table 2) using
approved AOAC methods
Table 2.
Samples
Protein
(%)
Ash
(%)
Reducing sugars
(%)
Total sugars
(%)
Ascorbic acid
(mg/100g)
Sorghum juice 1.12±0.1 0.92±0.02 2.95±0.02 18.50±0.1 10.8±0.9
Sorghum syrup 5.61±0.1 4.17±0.2 18.53±0.6 72.53±0.1 28.06±0.5
Squash 1.35±0.06 0.97±0.05 3.33±0.4 41.23 ±0.7 12.12±0.4
RTS beverage 0.30±0.02 0.20±0.01 0.90±0.1 9.80±0.7 1.4 ±0.3
Sensory analysis:
XX The sensory assessments were conducted at the Research and Development laboratory of NutriPlus Knowledge
Program, Agri-Bussiness and Innovation Platform (AIP)@ICRISAT. A panel of 12 persons consisting of staff
members and intern students of ICRISAT evaluated the products.